Let me explain, some parts of this, I have been working mostly as a UX strategist and growth hacker for a lot of startups and somehow I ended up leading a small social media consultancy and helping a lot of brands. (Don't ask me why - I have no idea - it just happened).
Facebook has always been a very weird communication medium, it's the only algorithmic communication medium that people actually use. One truth about this is, that 99% of all brands and companies are not able to use this, because optimizing your communication and ads for an algorithmic model is too complex. Brand Communication has always been quite simple: Find some values you want to attach to your brand, find something creative that sticks and mix these values and your brand... then publish.
Facebook is insanely complex, because you have a third layer: find something users want to interact with. Now you have three layers and those three are mutually exclusive for many brands. A Toilet paper company may find some ideas people want to interact with, but those ideas will probably not match their idea for their brand or values. And even if a brand finds a sweet spot between those three coordinates, they have to use right technique and be insanely creative to stay in that spot.
This is something brands and companies are learning very very slowly, so Facebook is not really changing anything in a way, it's just adapting to the situation.