Another factor to include is that as time goes on everybody adds more friends and more likes so the available consumable stream space is divided among more post

Another factor to include is that as time goes on everybody adds more friends and more likes so the available consumable stream space is divided among more posts. So this also contributes significantly to lessening the number of people who see your posts. But who knows what special sauce is in FB algos. If I were them I would certainly distinguish between companies, news/blogging, musician/art and image macro posters. Those all have very different usages and annoyance levels. Probably the interaction rate is factored in, but that also gets spread thinner and thinner. Obviously God and George Takei are winning the game, so the game isn't unwinnable.