first off; it seems to have worked in Britain. Have you seen the pool of leaders and politicians there compared to the US? Still dominated by the same elite schools, but much more diverse (ofc the diversity is literally skin deep but for the pure purposes of achieving this it does work)

secondly, have you ever heard of the Pygmalion effect? people aren't static. If you introduce somebody to a high performing environment and tell them they're meant to be there, many of them will rise to the challenge. Of course, there is room for natural aptitude -- but nobody is proposing the schools take entirely random people. They'd still be selecting the best of the cohort. People who were able to succeed dramatically enough to be noticed, just in different environments. Similarly, in your navy SEAL example, a lot is made out of the fact that soldiers like that aren't naturally born, they're made (through training, through the culture they have developed, the standards and professionalism they hold themselves to) Again, you'll want people with certain traits in the first place (low propensity for stress, high intelligence, high fitness, leadership), but to presume the current selection is perfectly meritocratic would be foolish, and its not like people are even suggesting that we don't try to select for such things, only to try and add another consideration to the mix.

The UK isn't a great example, because most MPs - especially in this parliament - are basically filler, with little or no real agency. They were parachuted into constituencies by the Party HQ, with no local connections, often against the wishes of the local members.

It's a nice job, but you have to toe the party line to get it.

There are still exceptions, but the days when the core of the Parliamentary Labour Party was made of people from all backgrounds are long gone.

The UK is actually run by a handful of industries - especially finance, defence, and fossil fuels - and there's much less diversity there, token or otherwise.

School/university diversity only goes so far to solving the problem. Outsiders will still be left out of the existing privilege networks for economic reasons - most people can't afford the annual round of skiing and yachting holidays in prime locations - and for social reasons, which include a lack of confidence, lack of familiarity with expectations and traditions, and outright bullying and abuse.

This isn't an argument against diversity, it's to make the point that breaking down the gatekeeping has to be the start of a broader process. It's not a definitive solution in its own right.

> Have you seen the pool of leaders and politicians there compared to the US

This has to be a joke.

>have you ever heard of the Pygmalion effect?

This social theory has been largely discredited.