If that's what they choose to do, sure, some steem will go back into the wild. But they can continue to cash out their sbd gains from posting and curation (maybe even self voting) and keep their massive power and influence.

And who is to stop some outside agent (let's say an account run by facebook) to buy a ton of steem and start using it in ways that are counter productive to the community. I don't see how its safe, fair or sustainable in the long run to have such a disparity in the distribution of wealth.

I do think there are whales who will work to push things in the direction you say, but the problem is systematic and cultural, not personal.