They will see a return. In fact they will see a bigger return when they don't upvote a single cent on themselves.
At the very minimum they will get about 1% interest on their STEEM POWER + curation rewards. Everything you self-vote on top of that is just greed. Just holding STEEM POWER already gives you better interest than some (or most?) banks give. When you include curation rewards, you can easily make 10% a year, which is absolutely insane.
Fair enough, by the way I like to share the wealth haven't got a lot to share but I always try to upvote posts I read and probably more so when people comment, thanks for your reply cheers mike