Well, the guys putting the money into the game are always going to demand a say in what is produced, as their bottom line is always to get more money out of the process than what they put in. For them, playing it by the numbers (what is going to sell) is the wise thing to do, because they really don't care about games other than as a way of making money.
With a company like EA, consider that their change of policy has won them support from gamers, but at the same time "The Escapist" has run other articles with others in the industry calling them stupid, and I believe pointing out that they haven't been as big a success on paper than they were when they were playing things by the corperate numbers.
Now ideally we'd have a situation where more producers and executives cared about the games themselves, but that isn't likely to happen until such a time as we have "Generation Y" filling those roles, which could take decades. Even so, it takes a certain kind of mentality to get into a position where you have tens or hundreds of millions of dollars to invest.
Trust me, I slam the corperate mentality all the time, and think it needs to change. I'm just saying that I understand the issue and all the idealism in the world is not going to change it.
Understand, a big part of the problem is that the guy(s) with the money riding on it don't just care about making a profit. If the numbers show that changing the lead of a game to a "Space Marine" could net them say 51 million dollars in profit unstead of 50, then they are going to demand what gives the least risk for the most profit. After all to the producer they probably figure (by the numbers) that most of the sales happen based on hype, and through pre-orders. Creating an "appealing" hero by the numbers means strong initial sales, even if the game blows chips overall... and what do they care if they make more money? If it doesn't work out for franchise potential they can just finance something else once they have the cash.
There is no easy solution since you really can't force a group of people to be satisfied with making a good profit, instead of constantly chasing a monster profit.