I think you are thinking of "merit" as some intrinsic property of a person as opposed to measured performance. Some things are hard to measure, but many things are not. Putting people into positions based on the best estimates of how well they would perform is meritocracy.
What is your system for selecting people for positions if not by how well they would perform at the positions? What this typically devolves into patrimonialism or clientelism...where positions are given to related persons, friends, or in exchange for political power.
Okay here's a good example:
A company hires and pays a person to do job a, said person has skills and knowledge of topics x and y and gets the job done using skills x and y.
The same company hires person b, who doesn't have skills x and y, but still has the accreditation. Person b, doesn't get the job done, still gets paid and the company did not have the problem solved, or service/product to sell.
Further, if we don't set rigorous standards for admission and graduation the smarter people have their accreditations devalued. Additionally, employers and other agencies will not know who they are getting.
The idea lowering standards so 'anyone' can get into anything is dangerous, and creates chaos. It's anti-progressive.
As for the argument that society will collapse because of the democratization of education and degrees and whatnot,it's at least a hundred years old argument. In France the right-wing has been whining about it for 50 years (especially regarding math) and we still have mathematicians that are among the best in the world.