Witnesses can give some of the money they make and this have some advantages and disadvantages. If they give too much money they might simply get outranked by other witnesses who keep more.
We shouldn't forget some people bought for many hundreds of thousands of USD worth of Steem. This is not speculation. This is well documented. This money trickles down sooner or later. Whales can't see all the posts being posted every day but sooner or later money trickles down and also Steem is getting more popular by the day.
Thank you for your input by the way.