Guys,
Is it a coincidence that this is called Robinhood?
COBINHOOD is already doing all that you described above. Their COB token also gives some pretty nice bonuses, like period airdrop of new tokens.
Trading with zero-fee
https://bitcointalk.org/index.php?topic=2169745.0https://cobinhood.com/For whose money will the exchange exist? Who will pay for the equipment, ervers. It also requires high costs for sacurity and personnel. Most likely it's just a marketing move to attract new customers. But after a while a fee will be introduced and the exchange will turn into the usual one.
To address your concerns: COBINHOOD makes money from ICO's which it underwrites, and from margin trading (which has a little fee on it)