Realsim and authenticity are two different things. Asking for "realism" is disingenuous, given that NBA 2K is a video game and video games are about creating your own scenarios. What matters is how authentic the players and teams involved act inside the scenarios you create. When two users are involved, you're both creating 50% of the scenario and you'll just have to deal with what the other guy wants to do.
I surmise not many players will be good enough to reach the summit and unlock the historic teams anyway.