All domains should really cost $1000/year from the registrar at a minimum to stop this idiotic "I'll buy thousands of them and sit on them forever until someone offers me enough for one of them to make the whole enterprise worth it".
Expensive domain registration would make it cost prohibitive for average people to start a website. The better thing to limit is how many domains you can own, or at least how many domains you can park.
There's issues with what's considered value, but our existing system is nonsense.