Sorry but that would not work. With a small understanding of how markets work can actually detect the error in this logic.
If the BID=ASK then that exchange will get flooded with trash orders. Nothing stops people from just buying and selling it back.
Now if you put a 2% comission on every trade to stop flooding then you end up with another problem.
Market making... You cannot have a controlled market without liquidity provider.
For a sell you need an equivalent buy, if you say the price will be "autofilled" then you need a LP to contain the risks, but they cant move the price without losing alot of money, if too many orders are open.
Say we got 5 million $ orders open to buy at 210$/
BTC, if we move the price down to 209$, who will cover the losses? If the traders can bid the price down and take the risk individually, then either the exchange or the LP takes the risk.
They will go bankrupt in 1 week, sorry, there is a reason why spread exists