The concept that was considered ridiculous was only giving rich people access to the resources to make it in a meritocracy.
But for a while, the UK actually didn't do that. New universities were created, "grammar schools" were mostly replaced, new hiring practices adopted, and the stranglehold of the establishment was broken a little bit, for a little while.
That was because as ridiculous as the original idea might have been, good people with good intentions started to believe in "meritocracy", and used the idea to make changes.