I think a big problem with Steem is that most people have the mindset of "bots are bad", especially from other social media sites, where flagging bots was what you were encouraged to do. It definitely wouldn't profitable, I don't get many upvotes. I still haven't made back the account creation fee (3 SBD).
My service was great for people that were new to Steem, and didn't know about claiming rewards (I reminded people to do that. A lot.), but I think most people just don't like bots when they come in uninvited, even if they are, in theory, useful.
RE: Are Resource Credits Preventing Spam? Yes (Proof Inside!)