Wow, this is a well thought-out post, and you raise some good points and ideas.
I am just a small "redfish" who has been here a few months, but I am well aware of the nature of "user generated content with rewards" sites from almost 20 years of blogging.
I believe that in a situation like this where you have "stake based influence" we end up with an unusual hybrid situation: We have to stop thinking just about content and start thinking of this as a social site which includes a lot of networking.
As a larger stakeholder, you're quite right that it would be impossible for you to find and upvote 1000 pieces of content a day! That's ridiculous!
Instead, maybe, we end up with a situation where yes, you vote for the content you really like to some extent... and the rest of your — let's call them "$10 votes" — are given to people. Perhaps they are not the greatest content creators, but if THEY are out there reading and casting their smaller votes for 40-50 pieces of really good content every day (and I know quite a few who are) they add "value" to the Steemit ecosystem that merits one of those votes.
It is not merely a reward, it is also a form of encouragement: They will feel like they should continue to be "very active" because their efforts are rewarded... it's a little different approach from delegations, in that it is a direct reward, rather than an indirect one.
I say this as an active interactor/curator... I am fortunate to have two nice delegations from more more senior Steemians, but whereas that is wonderful, what also really helps is that occasional larger vote that allows me to power up my own SP on a regular basis (I have never taken rewards OUT of Steemit, except to pay for contests I had), so I can continue my work of curating, once those delegations go back to their donors.
Communities are built by PEOPLE, not by bots, code or systems. Those are just a *framework," in my opinion.
Anyway, thanks for a thoughtful post!
=^..^=