I'd sure as hell play it. APF2K8 and NCAA 14 are the only reasons I still sometimes turn on my Xbox 360. I dug the roster of legends and the format for how teams were put together. Even without a multi-season franchise type mode it still holds up as a fun game to play. There was a foundation to build on if it could have generated a bigger audience at the time. The fact 2K8 was in the title suggests to me that may have been their intention.
If I were to hazard a guess, I think you answered this in part. They'd maybe have to start it from scratch, which could be costly. Given the lack of commercial success with 2K8, it's a gamble. And they're weighing that opportunity cost against other development that may have a clearer path to success.
That said, it's been 13 years. The market is different. There are different ways now to monetize such a game. I won't hold my breath but if they ever took another shot at it, I'd wish them success. Sports gamers deserve more variety.