As usual, you are directly on point. Thank you for addressing this. Of what you said, this is what I would like to expound upon:

...by allowing pages to reach people, Facebook are leaking potential profits. It's a corporation that understands data and understands optimization. They have managed to make their advertising product one of the most popular ones on the market and they know that after expansion, it's time for optimization. All of this is about cutting the free-loaders out inevitably converting a portion of them to advertisers.

I know this to be true personally, because I've been experiencing it over the last two years. A page will spend quite a bit of time trying to amass a sizable amount of followers through engaging posts, only to have a smaller portion of those followers at any given time even be SENT said posts, paid or otherwise. It's one thing if they get sent and then people don't see or interact with them. It's quite another when those posts are never sent at all.

All because their servers can't take the strain. Or because people are complaining about seeing too much marketing posts in their feeds. Blah, blah, blah.

As you say, Zuckerburg and company are not stupid, so the only other alternative is, they never intended Facebook to be a marketing tool for businesses, period, and while they entertained the notion, they no longer want it. You advertise through them. That's it. No more pretending.