Running the matching engine at discrete times doesn't eliminate the speed race, as that's mainly about jockeying for queue position. You could put in an auction instead, but that's just changing the rules of the game rather than eliminating the game.

But really, the key thing is that liquidity provision actually is a service -- market makers are basically selling insurance. There's money to be made doing his, so people will compete to do so. That's what the millisecond race is about. Faster trading -> less risk for the MM -> less capital needed -> lower profits acceptable. Contra what you're claiming, the race is cutting into profits, not raising them.

If you want to reduce market-maker profits, crack down on payment for order flow, and let everyone compete for a chance to trade against it.