It is perfectly acceptable for an apartment building to have accessible and non accessible units. The ADA isn’t that crazy, which is why wheel chair bars are probably not in your bathroom.
I'm not disagreeing with you there, the term "accessible" has a wide range. But it would be inappropriate for a building to have some units with e.g. steps and some without. I'm not sure what you been by wheelchair bars, but if you mean handle bars my building accommodates those through a reasonable accommodation request although I have lived in buildings before which had them in every unit.
It would be completely appropriate, and in fact that’s what happens. We had to turn down a nice one bedroom in a new downtown Bellevue building because it was a split level with a walk down (and we have a toddler so....). Most of the units were not like that, and this one was cheaper as a result.