Right- the current state of affairs serves the top-tier MBA programs, their graduates, and management consulting/ banking/ PE firms very well for the time being.
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).
Although the concept of meritocracy has existed for centuries, the term itself was coined in 1958 by the sociologist Michael Dunlop Young in his satirical essay The Rise of the Meritocracy.
In any case, I'm not defending the MBA industrial complex, but it is an attractive, valuable, and stable system they've set up. I definitely got value from it, but fair it is not.
Silicon Valley/ VC-land has a seemingly more egalitarian system on the surface, but if you dig even an inch deep there's a lot of ugly stuff there too.
Certainly not for the MBA programs and their graduates.