The trending has been amazingly better since these changes. And people still use upvote bots to advertise stuff it just comes with people not getting any ROI because of some downvotes... BUT they still achieved their goal of getting a post into "trending" so their marketing dollars seem to still be working.
So i hope @booster and a couple others stick around I see no issue with a few sticking around. If i had something I wanted to advertise I'd use booster and others AND i'd say at the end of the post that I don't mind and even expect it will get some downvotes because that's the nature of steem. I expect to not get a free money because of advertising I expect that exposure actually costs something.
And finally promotion should be more in the hands of the UI anyway. Let's hope interfaces make some changes to help give users an option to advertise things they find important.
RE: You will never make money preventing others from making money!