I think we could probably go back and forth all day in this regard. As in, while your non-OS friends and acquaintances have ranted and raved about how great the story mode is, my non-OS friends have been on the complete opposite side of the spectrum.
Almost universally, all of my acquaintances with which I've discussed the storyline with or have experienced it firsthand find it corny, unrealistic, and in many cases, laughable (particularly in the case of the voice acting and dialogue).
Moreover, even amongst the sports series for which I do not purchase (EA's NHL, for instance), the last thing that'd reel me in would be an artificial storyline where my created hockey player would speak with an overly embellished, stereotypical Canadian accent while being forced through an awful & singular career storyline. To suggest every other sports game forum is looking to precisely replicate 2K's corny & singular storyline to a T may be a bit misguided, for that is not what I have seen.
That said, I do believe there's something to be said about the popularity of game aspects that may be a departure from its simulation roots while perhaps sacrificing what one would deem to be "quality".
Virtual Currency, seven-foot created players vying for superiority in fictional parks, the corny MyPlayer storyline... I think many of those things could be argued to be in contrast with NBA 2K's initial mission ("Basketball's #1 simulation"). However, it's a situation of "What sells, sells". 2K, afterall, is a business and to a large degree, it's going to be about how to maximize profits. If I had to guess, the artists who literally make the game (programmers, designers, etc.) have likely objected to a number of the direction changes made in recent years.
Just as few would argue for the artistic quality of the "Fast and Furious" series, there's no denying those movies have been wildly profitable nonetheless. Similarly, in the case of Virtual Currency or awful storylines, they could lead to an uptick in profitability, but that's not always in direct correlation to quality.
EDIT: All that said, it's unclear exactly's shaking out in 2K16, so this was more in reference to previous iterations.