How many steem will the large stakeholders allow to go to which accounts.

This is a very misleading statement and a major part of the reason for the mindset that is so prevalent out there.

The largest accounts control 53% of the SP. Let us suppose that there was 100% activity and upvoting by all accounts. That would provide the larger accounts with 53% of the take meaning that 47% went to everyone else.

The challenge with this is the breakdown of 75/25 breakdown for the author curation. Most of the Whales do not post a great deal. Besides, that small a number cannot possible keep up with the amount of posts that the other accounts can do meaning the rewards will be skewed in that direction.

The days of looking at this as "everyone but the whales are helpless" are passe. That view is a cancer on the blockchain that needs to be cut out. Even if the Whales did not power down over the last 19 months, the other accounts would have had a similar jump in SP.

....Which begs the more important question....why are they selling....?

We know a big part of it was Steemit Inc powering down for a variety of reasons but, in the end, who cares? Many did not like the existing power structure so, now, we see it shifting with powering down, and people question that.

A flip question is might be why are many Orcas powering up?