If somebody has means and desire to make a new exchange why not, but to make it work it needs a lot of money and effort and like you mentioned "some truly insane idea" to stand out from hunderds of them. I personally wouldn't go in such business now.
Lately i see many new crypto exchanges / shitcoin exchanges.
I find that creating new exchanges these days isnt profitable anymore, why would someone switch from a long known exchange like binance/coinbase/etc. to some brand new exchange? Even with a marketing campaign, theres not much you can innovate. All exchanges that promise "no KYC fiat trading" is either a scam or will be shut down due to AML policies.
Exchanges which allow anyone to list their own coin ( exists ) are very vulnerable to Dip and Ditch schemes.
Overall i find working on a new Crypto Exchange a waste of time, money and effort unless you have some truly insane idea.
Am i wrong? Correct me if im wrong, willing to hear all your opinions.