'90s, not '90's...

"The most common and widely accepted way to write the decade is '90s, with an apostrophe to indicate the omitted "19" and an "s" for plural. Both 90s and the nineties are also correct, with the former serving as a simple plural and the latter being the full spelling. However, writing it as 90's (with an apostrophe before the "s") is generally considered incorrect for a decade, as the apostrophe is reserved for contractions or the possessive case.

Come on, 2K...

I haven’t checked 2K’s credits but my guess is that they’re not bothering to have a dedicated copy editor / writer on the team; they’re likely just winging it (i.e., copy is just being written as needed by people whose real jobs are something else). Copy standards have been declining generally over the past few decades, in large part because digital formats have made copy correctness seem less urgent (since, once an error is noticed, it’s much easier to fix than if it had been a print error; we see the same attitude in game development, i.e., it doesn’t matter if the game is a mess upon release, we can just patch it later).

Also, I suspect people read less now, at least in terms of polished copy (i.e., not online discussions, etc.), which naturally translates to being less fluent in existing language conventions (I hesitate to say it represents a decline in literacy, because it’s really just a different, sort of pre-20th-century flavor of literacy). Anyway, point is that it’s a vicious circle, wherein more and more people don’t read enough to notice these errors, those people join the workforce and proceed to both make and not notice these errors, while also not valuing the expertise of those capable of avoiding or catching them (again because of general ignorance to the prevalence of such errors), then a new crop of people consume that error-riddled copy and themselves go on to perpetuate the same ignorance.

It's definitely a common mistake when people abbreviate decades. NBA Live made the same error with their All-Decade teams, going right back to NBA Live 2000 in 1999. In other words, the "90's" mistake goes right back to the 90s! (Or the '90s, as the case may be.)

And yeah, it's always kind of bugged me as well, in basketball games or otherwise. Apostrophes seem to trip up a lot of people.