You're right. Now there are so many new exchanges of AMM type where all exchanges will be done with automatic swaps without any bids and offers, there only have liquidity and can be revoked at any time and it will make a loss to anyone who buys them instantly. In fact it seems to have an impact on the cost of gas transactions on eth. you can check it directly at https://ethgasstation.info/. I hope it can be handled by some new project in the future or even when eth 2.0 is properly released perfectly.