Uniswap already has mainstream adoption lol. V2 has had more volume than Coinbase for almost a year and its less than a year old.
People that want alpha learn that interface, the end.
If you want limit orders and big ole' chart taking 3/4ths of the screen so that you can pretend the Bollinger bands are suggesting a breakout, then you have to use third party GUIs, it is all possible and there are plenty of github projects about it. Uniswap V3 makes that even easier.
HFTs already exist here, they provide a service mostly liquidity depth. Crypto exchanges are fairly unique in that they operate many conflicting roles when in other markets they would have fiduciary duties.