Can I just note that those are two different things.
people who earn rewards through the existing algorithms without social content
and
people who keep selling their steem.
I've seen bloggers receive good earnings also selling such rewards rather than powering up.
Is there some other, more fundamental reason, why neither of the above examples is compounding their rewards?
Give a reason to power up? IT's hard to find a good reason when the content discovery is broken and the incentives for becoming a whale are being diminished on the other side.