Earlier quoted context omitted.
A problem for who? Certainly not for the MBA programs and their graduates.
Inverting your response gives the answer: anyone for whom those programmes are not attainable, or from which they're excluded.
Top-tier MBA progams' whole pitch is about how getting in to these elite institutions confers massive benefits to the rest of your career- they certainly have no incentive to change any of this. The employing firms get a veneer of shiny "elite" frosting over their staffs (and they're mostly selling the abilities of their staffs)- the current systems serves them very well too. Being egalitarian would have some feel-good optics (maybe), but isn't in the interest of any of these entities.
These old-school institutions aren't where you go if you want something that reflects Silicon Valley-esque "meritocracy", where credentials don't matter and only impact does. That's why this ethos is a big deal, and different than what came before (though it has its own set of issues).