Wait, what??? Think really long and hard about how that would play out. This is a scarce resource, that like many digital items feels cheaper than it really is. I personally think that domain registration should cost more. That would a) stop casual speculation and b ) make those speculators feel like holding on to a domain less appealing. I own way more domain names than I have time to work on and until there is any reason to stop renewing them probably won’t.
Perhaps you could have a ratcheting cost, where the first 100 domains are $10 each, the next 100 are $20 each, and so on up to some upper bound, with provisions for shell companies that solely register domains.