Sure AI could do this on a personal level but communities are built around shared experiences so we might see some major labelled variants emerge that shape new communities.
Each could even have an internal product owner trying to beat the others. Its a simulation of competition which might drive some innovation from Google once again (assuming no real competition is breaking through that market domination anytime soon)
The internet is the way it is largely because of Google's algorithm and people shaping their content to appease it. If they allowed several to exist, we could have several internets also existing without the need for a new walled garden.