The downside with this is the "regulatory moat". If this hypothetical regulation becomes hard to meet, then only a few companies are able to comply with it and

The downside with this is the "regulatory moat". If this hypothetical regulation becomes hard to meet, then only a few companies are able to comply with it and it inadvertently reinforces their position. What I would like to see is a requirement for platforms to be open, so they can't take data and networks of people hostage by locking things down. An analog is portability of healthcare data: one hospital or EMR vendor can't lock up data for themselves, they must make it open to others (though they still drag their feet and don't always make it convenient).