Well, then I'd lean towards the somewhat disturbing possibility that most of the large stake holders are so automated that everything stays pretty constant. Seems a little too even for my liking, but let's just say that whole large account SE Asian contingent run on some kind of system where they automatically power down every time they add 5,000 Steem (or whatever) so their stake never really changes by more than base inflation, over time.

Most of the South Americans and Africans power down in perpetuity because they need every cent to simply scrape by, so there's very little change there.

Which leaves a pretty small contingent to actually move the needle... but that still doesn't explain why it's so constant vs. the price of Steem. I'd expect way more price elasticity.

I'm just speculating... getting further might call for a major deep dive on STEEM movements through various exchange accounts still active here.