I agree that's part of the problem, but not the whole picture. The business models behind these companies is what influences the algorithm.

Also there's the designed algorithm that optimizes time on site by decidcing what you see but there's also an implicit algo that is being hacked. Its our basic primate brains that were never setup for the potential of social recognition by more than our village. Checking for a new like, a comment etc, that's what hooks us, then the algo adds the jet fuel on top.