People forget that the MLB franchise was a mess for many years before 2005. That game hardly became great during a one year cycle.
Companies would have to figure out a way to make the off year profitable, either charge $60 for a roster update or charge $130 for the game every time it comes out and give free roster updates during the off year.
Money is the bottom line but things are slowly starting to change for many gamers I know. The five buddies of mine who are pretty hardcore with sports games haven't bought Madden in at least three years. I just sold my 360 and all my sports games in favor of a Wii. The sport-game industry is dooooooomed, IMO. It's sad when you compare it to other genre's on the next gen systems. So just from myself alone there's $200-$300 that EA and 2K won't be getting any more. More and more are going to bite, even if there still are a good amount of sheep left out there.