Well excuse me to burst your bubble, what grander scope implementation are you talking about? Oh wait you're just dreaming. You think it's easy and cheap to distribute work tasks across millions of clients and take a beating from millions of hashes submitted each second?
You're contradicting yourself. Earlier you ridiculed calling it 'fair payouts' and now you are telling us (correctly) that there are significant costs to provide this service.
There aren't any real barriers to entry here. If someone can offer a better deal to web hosts looking to monetize, they will.