Frankly, a lot of what people refer to as "prop trading firms" and "quant hedge funds" on here are just market-makers...they are taking very little to no risk, a lot are just riding the wave of ETF growth. Even the ones that are running alpha, I have heard of a few strategies, and they are largely what you would expect: low-edge, crowded trades (frankly, a lot of it is LTCM-style stuff).
That is why the business has become more tech-like, because actually taking risk is...quite risky. If you are going for alpha, you are trying to hire one guy out of thousands, that person knows what they are worth, etc. It is far easier to hire lots of devs on low wages and do the grunt work jobs that are less lucrative, but don't require being able to actually work out if someone is a decent earner.
Man Group has their own department at Oxford Uni, I think Winton hires people out of their department at Cambridge...Man Group's shaky record is legendary (they are doing everything now that blew them up in 2008), Winton was top tier...not anymore. AQR is another one, although a more traditionally finance quant approach...it all turned out to be pure beta. The hybrid approach of hiring devs or ML PHds to generate alpha has only ever worked accidently.
The firms that have been printing money from quant investing over the past five years have all been traditional hedge funds that incorporated quant methods into a fundamental process. And I expect that will continue because, bluntly, these firms know what the price of a security should be better than some busted factor model.