Your theory seems sound, but it doesn't take into account niches. For example, my area is gardening and homesteading and the only account on here for that interest who might be able to give a comment a vote of that value is @papa-pepper. As you can imagine, he is only one account, so although I've conversed with him I've never had an upvote from him. He prioritises the people he can also work with offline, as he should, because that is what homesteading is about.

Okay, I'm willing to concede that increasing the comment payout might sort out the wheat from the chaff, but I've been here a while and my full upvote is still not at that level. After all the work I've put in to trying to increase my SP I'd be really disappointed not to be able to reward an amazing comment with a payout worthy vote. I've only recently discovered that I need to get it to 0.02 or more to even net them a payout, so I've been increasing my votes or not upvoting at all.