The phrase that struck me in your post was "business plan" as in "have one". The advertising for steemit isn't great. Lots of people have spoken about the Trending page. The other thing that is problematic is the external promotional message running along the lines of "have a voice, make money doing it." Some people are going to do that, either by luck, higher investment, previous reputation or ... having a good plan. But for most people, even with a plan, it is going to be like any other start-up business in any other environment - hard work with no guarantee of success.

People who are doing curator/mentoring type stuff put in a lot of hours. Some of them, I don't how they manage it. So I was relieved when I learned that there are different models where their work can be rewarded. I don't know @sndbox, so difficult for me to comment but I admire the proposition behind @steembasicincome. That project isn't offering mentoring support or validating/curating quality, but it does have an element of mutuality and reciprocity so it is in every sponsor's interests to support participating, quality accounts.

The other project that I've come to know a little about is the @runningproject. This does offer votes for ever on all your posts, but there's an approval process (examples of quality posts) and an enrollment fee. For a whole range of reasons, I think @runningproject is important (I'll write a post about that). It's supported by @isotonic - a voting bot - with 90% of vote-buying income going back to the investors who have delegated steem power and 10% going to support and grow @runningproject.

I'll also mention @treeplanter and I am sure there are many other examples. These all seem to me to be examples of the potential positive benefits of vote buying.

(I agree with your point about vote-buying as a simple transactional exchange is not a great idea).