Except that 99.9% of people will buy "stable" coins on Coinbase. Not your keys, not your crypto. If Coinbase gets leveraged or goes the way of SFB, you have literally the same non-immunity as a bank run except you also don't get FDIC backstops.
Yet, non-custodial holding is becoming much easier and safer.
Crucially, wallets are improving a lot, and a spectrum of custodial options is developing, with rich tradeoffs in eg. safety and self-sovereignty.
For example https://www.coinbase.com/blog/how-smart-cryptography-makes-c...