but I guess the same can be said for voting up any other popular author with a history of high value posts

Exactly. There is another effect too. The more of these posts there are, the less each one is worth, meaning smaller "windfall" curation rewards to those few voters who are in early, and more opportunities to be early on reliable posts (which in turn tends to spread out curation rewards more widely). There are a lot of zero-sum (in the short term) aspects of the reward pool that end up being self-balancing.

I wonder if the inflated price of SBD is being done specifically to inflate the rewards pool for the advantage of those earning through the rewards pool

Interesting possibility. I personally doubt it and think it is just speculation on a token that, to the extent it is already well above $1 becomes somewhat free-floating ($1 is too far away to matter). But I don't rule out other possibilities.