Earlier quoted context omitted.
This doesn't require algorithmic feedback loops. People simply would seek out (and create) content which provides inconsistent rewards. A slot machine simply needs a random number generator with a certain small chance of jackpot. The null model here is what can be achieved without individualization.
That doesn't mean it can't be optimized with algorithms. Obviously that's what they think they're measuring and doing, otherwise it would be random.
I'm not sure "randomness" is the general property, but rather unexpectedness. The content-provider may well be following a "formula" like with fiction plots, that give the protagonist setbacks and victories. Facebook uses approaches which try to profit within the constraints of a relatively small group of programmers trying to make money off billions of users. It doesn't mean these approaches are the best overall at serving the most desirable content to any given niche of users. Or even the best at making money qwithin those constraints. If are to believe in "network effects" (the other popular basis for calling for a breakup of Facebook) Facebook is simply succeeding because it is there first. Rather independent of this claim that they are winning by being the most competant.