Because the market is clownshoes, top to bottom.
Users are clownshoes: they are gambling, and so they overvalue ability to move money ~instantly in and out of exchanges. This results in exchanges competing on custodial risk. The winners lose.
Root any computer at a Bitcoin exchange. Get all three.
See that's the thing about regulated markets: you're allowed to sell *products* which are risky but the *system* risk should be close to zero.
Do you know when the last time a bank or brokerage has lost $50 million in customer money was?