Damn this sucks if you are correct. Playing a franchise with the 91 Lakers was the one thing I was most excited about.
What's even MORE disappointing is that a couple weeks ago a good friend played 2K11 (he's a video game reviewer for a newspaper), and I specifically asked him whether we could take classic teams into franchise mode. He said we definitely could. That leads me to believe the feature may have been pulled late in the development process.
This is all speculation of course, but it doesn't look good from where I sit.