I am not aware of existing witnesses sharing their revenue with their voters - do you know of some that do? I know some witnesses auto vote users that they support - is that what you mean? Until my witness server gets higher in the list it doesn't actually generate much Steem payout - it's the top 19 Witnesses that get high payouts.
My general intention for my witness payouts is to use them to firstly cover my costs and to secondly then use them to develop projects that generate value for the Steem eco-system. This is most likely to include software projects such as new apps for Steem and also some marketing for Steemit on other social networks, such as videos for Youtube that educate about the benefits of Steem.
Currently some of the top witnesses are the operators of the paid upvote bots, so they are making huge amounts from Steem and there would not be much chance for me or many others to match their ability to pay out votes to those who vote for them as witnesses. For this and other reasons I am more focused on creating software solutions that might balance the eco-system in a more effective way than my own upvotes ever will. More to come asap!
No, I am saying that the upvote bots that users pay money to, to vote for their posts are being operated, in some cases, by top witnesses - so it is the other way around.. these top witnesses take money from users and SELL them votes.