Why this indifference/discrimination against post-MBA associates for Buyside Recruitment?

Something that has been bothering me is as I have become more & more active on this platform & Buyside in general, why does it seem that exit opps just seems to drop by 80-90% if you are coming as post-MBA?

Like pre-MBA IB analyst/MBB ->Buyside is well established but somehow Post-MBA IB associate ->Buyside is impossible but why's that?

I get argument that "Too senior for junior roles & too inexperienced for senior role" but what if someone is ready to accept pay-cut & junior roles just for a career in PE? And I am saying this as someone who already has a MF (BX/Warburg) PE associate experience but in a different country so it's automatically discounted in US PE recruiting. Post-MBA-> BB/EB IB is only way to build some experience in US & then try to land in PE shops.