That stays the most fitting metric for facebook though: the bulk of their revenue comes from advertising, and anything related to ads needs your presence: they

That stays the most fitting metric for facebook though: the bulk of their revenue comes from advertising, and anything related to ads needs your presence: they need data to target you and increase ad price, and they need your eyeballs to be there to watch those highly priced ads. There's just no way around it. Meta might come up with different revenue streams and different strategies, but for the blue app that ship has sailed.