Probably the most critical problem that most game makers share is that of not understanding their customers. Publishers often throw huge resources into developing and publishing a game, advertising it, and doing PR for it etc, only to have it fail in the market. And then they blame external forces for this (market conditions, piracy, the recession, whatever).
The mistake that they are making is failing to build a compelling story. Not a game story, a marketing story.
Every succesful console platform ever has basically worked because it embodied a great story. The Wii is not just a device that handles gestural controls, it embodies a story of inclusive gaming for middle class suburban people who find videogames scary. The Playstation used to be a story about a kind of rave generation cool (before becoming a negative story of brute force). Xbox is a partially successful story of connection, a story which Dreamcast also tried to tell but was too soon for.
Stories apply to big game consoles and small indie titles alike. World of Goo is a great little game and also a story of idiosyncratic indie success. Darwinia is a story. Castle Crashers is a story.
Compelling stories draw players in. They make them long term customers, not short term consumers. Why? Because people like to be a part of something.
The publisher model basically thinks of players like the sea: they think they have no memory and are essentially in search of distraction. This is not at all the case. Players want to be members. They want to belong. They want to vote with their wallets for the guys they believe in.
This is why the most important thing that any game maker can do is to get the e-mail addresses of their players to build a club. And then treat those e-mails with respect and not as just another advertising channel.
Lots of players out there want to be members of your treehouse. How hard are you making it for them? Could you make it easier?