(WARNING: the post contains a few spoilers about Echo Bazaar.)
(also: I didn't actually learn these things from Echo Bazaar, it just made them apparent)
Echo Bazaar works on a very familiar base, instantly recognisable to any roleplayer: unlocking content through progressions. As you "level up" you gain stats, traits and items that allow you to acceess new and different areas of the game. I'm not just talking about exploring places, but exploring game content. This includes stories, people, ways to solve problems. Sometimes a problem will have only one or two solutions, but a third becomes available if your stats are high enough or if you have the right item or whatever. So: exploration. This is the fundament of all roleplaying games and Echo Bazaar does this pretty well.
But the exploration is very tightly tied to your Stats increases. Once your stat is high, you can't go back and do low-level stuff. And while some options require items or other qualities to unlock, to get those items and qualities, you need a certain level of stat first. So, once your stats are high, you can't go back. But once you hit the maximum of your stat, there is nothing more to do. You're stuck. There's no more content to explore.
This is most apparent in videogames, where exploration is usually very limited to a set of options. In MMORPGs, we are given the illusion of greater freedom, but it's still fairly limited. MMORPGS have another problem. While much more "open" than their solo cousins, there's usually no "end" condition. A solo game usually has some kind of story or at least ending that the player drives to. Once you finish the game you know you've finished and can leave it satisfied (unless it was a crappy ending, it happens). MMORPGS however (and Echo Bazaar falls in the same box) don't have this benefit however. Being "persistent" worlds existing for many, many players at once, these worlds must preserve the status quo and remain persistently "open". But content cannot be infinite, so you hit the roadblock sooner or later. WOW has an "endgame" but not an end of the game. Once all your stats are top and your level maxed, you can just fight other players and kill the same boss monsters over and over. Exploration dies out.
Once all my stats are at 100 in Echo Bazaar, I have not reached the end of the game, but the game is over. I can't really help the anarchists overthrow the Masters or actually win the Great Game or whatever. While I'm raising stats and exploring, this can be a tantalizing posibility, a reason to drive on. But once you hit the exploration roadblock, you realize the game is ultimately static and limited.
But it's a FANTASTIC illusion while it lasts.
2. Player/Character Motivation
Echo Bazaar does a really neat thing where it offers you to gain an Ambition for your character very early on. This is a sort of personalized storyline (there are probably thousands of people out there playing that same storyline, but it's separate and individual from the rest of the content). This gives your character (and hence you) an ambition, a motivation, something to strive for. You know what to go for in the game. You know that to learn about where the diamonds are, you have to talk to the music-hall singer, then you have to find her, then rescue her, then soothe her...etc. Classic drama cycle
a. What does the protagonist want?
b. What stands in his way?
c. How does he deal with it and what kind of new situation does this create? (go back to a.)
The rest of the game doesn't have this kind of motivation built in. You are free to explore as you wish and even if there are plenty of reasons to be motivated - goals particularly based on exploration ("Who is the Topsy Ting?", "What is the Museum of Mistakes?", "What's in the Forgotten Quarter?") - they don't have quite the same traction and focus of a personal, long-term drive/story. Ambitions are quite lenghty, but are not finished yet, and a motivated player will reach the last available snippet of story quite fast. So even if you haven't reached the end of the rest of the content, once you get to the last signpost of your Ambition, the game loses a lot of flair.
3. Calculating resources and lack of real consequences
When you interact with certain creepy stuff in the game, you get Nightmares. Or when you do dangerous stuff, you might get Wounds. It's pretty scary when you do so for the first few times. "Oh crap my Nightmares just went up, oh my!" It gives you a sense of actual danger, it's a consequence to your actions. It makes you wary of what you're doing and consider your options. "Is this worth it?", "Am I willing to risk for this?"
But then, after a while, you realize these consequences are pretty much very predictable in almost all instances, to the point of mathematical precision. I know exactly how many times I can have a bad dream without getting taken to the Asylum. Sure, this is an element of Exploration, too. Exploring the system, figuring out your best options, discovering what does what, what works and what doesn't. But like most exploration, it disenchants the subject of your study.
As I said, I know exactly how many times I can have bad dreams without going crazy. And once I hit a particular point I stop, and drink some laudanum. Or some good wine. Or just stroll around the university gardens and relax. Or whatever. It's not a consequence anymore, it's an annoyance. It has no impact on what's going on, except making me do some other stuff to remove the effects. It's like Hit Points in D&D once you get healing spells. You fight fight fight until you're almost at zero, retreat, heal. No consequence. No real consequence at least.
Or like darkness in dungeons once you have the Light spell (and sunrods and sunstones and all that jazz). It's not a threat but a distraction. You go till a certain point and then you safely remove any "bad effects", to the point where everyone starts handwaving it. The DM stops describing lighting conditions in the dungeon because if he says "it's dark" someone is going to say "I have darkvision/I cast a Light spell/I activate my sunrod." You start ignoring it, it's not relevant. But instead of ignoring it in Echo Bazaar, I have to go and get rid of my Nightmares every once in a while.
There's no element of risk, or gambling, or judgement, merely a cold, strategic, calculating decision about when to lower one set of numbers and raise another or vice-versa.
(the rest of the post some theory-jargon in it)
So, I think that's actually breaking the Czege Principle in a weird way. The Czege Principle states that when a player both creates adversity for himself (his character) and resolves that adversity, the result is boring. When I'm clicking those dream cards, I'm making my Nightmares go up, I'm making trouble for myself. But I also know exactly how much trouble I can take and I know exactly how to make it go away. In a way, I've already resolved the trouble, it's a needless cycle.
To continue with consequences:
A similar, but different thing happens with the story itself. When deciding whether to kill the Cheesemonger, help her enact her plan or do something else altogether, you action will have no consequence to the story. Yes, perhaps your personal story. You will be able to say "I killed the Cheesemonger." or "I helped the Cheesemonger kill the spies.", and it will be YOUR story. Emily Care Boss wrote a couple of great articles over on the failbetter games blog about how Echo Bazaar supports the Right to Dream: you never have to do anything that doesn't fit your character, you probably will, but you don't have to. It doesn't really challenge your character concept, except maybe a few rare times (like when the game says "To get to Z, you will need Y. And to get Y, you will need to do Q." and your ideal Dream is both getting to Z and NOT doing Q). So yeah, your story.
But no matter which of the options I pick, the Great Game in Echo Bazaar will stay the same. Nothing will really change. The spies will keep on spying. I guess this can be also interpreted as a thematic statement ("one man can't change history" or something of the like, something about the futility of struggle against the establishment maybe? or how fate is stronger than free will?), but it gives you no options to actually challenge that theme. It's Right to Dream again. "This is how it is. This is how it shouldn't/can't be." instead of "What are you going to do about it? What will happen? What will it mean?" So, yeah, no meaningful consequences in the Story Now sense.
P.S.: In no way is this a criticism of Echo Bazaar. It's a fantastic game. I'm merely trying to find the elements that make games sing when they are present and make the game flat when they're missing. The Echo Bazaar guys can't give us infinite content. It's not their fault.
The second bit of my third argument is mostly a matter of taste, but I hold the first two to be largely universal. Particularly the first one.