Now, of course we could do this probably without spending so much on ads, but just saying ads are zero-sum is incorrect, because there's a bigger picture.
Social status is again not so simple. Because after a certain group size there will be value in being different. See also the classic equilibrium between strategies in any game (as in game theory).
That said, yes the race to the bottom is a real problem, see the oft cited Meditations on Moloch: https://slatestarcodex.com/2014/07/30/meditations-on-moloch/