Many sellers can't afford to do a renovation and even if they can, they don't have the knowledge to do what the market wants. (They can't borrow without both equity and the ability to repay.) They also may not have the time.

Many buyers aren't interested in doing a renovation, and most of the other things apply.

People who renovate for a living do have those things.

You seem to think that holding out for more money is no-cost - you're wrong.

Flippers lose money if they're wrong about the market, so why are you so insistent that it's wrong for them to make money?

Which reminds me, how long does someone have to own something for you to be okay with them selling?

I won't repeat what I said about flippers since I replied to multiple other comments but they would still exist but provide flipping/renovation as a service(see other comments).

People can sell whenever they want, my restriction is the profit margin. I have no problem with that margin being more and more over time so long as that rate is nationally set to be uniform.

Are you going to cap the amount that flippers can lose as well? Why not? And, why should their profit be uniform? (Some flippers are better than others.)

Flipping as a service requires waiting by buyers and/or sellers which costs them money. Why is that a good thing? (A renovation may take 6-12 months.)