Don't rely on exchanges not to sell us out, we all know how badly exchange are licking the government ass just to get want they want.
That's the more reason why the feature OP is postulating isn't even advisable, centralized exchanges even though it is user-friendly also has its own disadvantages on the basis of privacy (users must submit KYC documents), as users information can be handed over to the government at their request. Thhat act in itself counters decentralization, but it is what it is, and that's why they are called 'centralized' exchanges, controlled by a third party, thus users should not store their coins in web wallet of a centralized exchanges as "if it's not your keys, it's not your coins". Having said that, dex users wouldn't want dex exchanges to have any form of centralized feature which OP's suggestion would create.