Apple turned off a lot of "signals" used by advertisers for precisely targeted ads via persistent user-beacons. Facebook ad placement quality (and revenue) cratered in the immediate aftermath.

Meta has since gotten better at it- likely with lots of AI-assistance and their revenue numbers reflect this. The targeting is now likely probabilistic in that the advertiser now makes educated guesses on the best ads to serve based on limited or non-existent identity information.

So the AI efforts would have paid back by way of higher revenues.