It's simple. Other than perhaps OTC, which is KYC anyways, there is no possible way to safely purchase the amount of Bitcoin required via p2p only for many people.

Say you need to purchase $500k worth of Bitcoin. Or Monero for that manner. Go ahead and get that P2P. Bisq? lol, sure. You could get MAYBE 50k and get raped on the spreads. maybe. more like 5-10k tops in reality these days. Then you have trust and security issues with bisq. Virtually no dex can handle that in any way.