Assuming we go with only the uniforms currently in the game (and there's more than 123 teams; you should count again) and if we figure one main and one alternative for each team that's 254 uniforms. Considering the amount of bitching about the various schools (this jersey isn't the new one, we just announced this one, what about that one) I'd say we can safely triple that number for a total of 762 jerseys.
Where the heck do you think those things come from? They just appear out of thin air? They take time to create. To top that off the art department is working on NCAA 14; or did you think they weren't going to release a game this coming year? Think about what you're saying, man. It's just not feasible for them to release all the uniform updates everyone wants AND release a game in the coming year. What would you rather do, play dress up or get a new game with some new improvements?