Nothing. More dark patterns to trick people into accepting tracking. Look to how the industry reacted yo GDPR.
> personalized ads that creep on you were essentially made a load-bearing column of the Internet before anyone knew how creepy they were going to get with it
You can have personalized ads without invasive and pervasive tracking
Anecdotal observation from big-ish corps in EU: everyone started trying to look very mindful about what data they ask for in the first place, what gets stored where, what is shared with whom. In some cases, this led to actually being more mindful about those. At least in e-commerce, GDPR worked in the privacy-minded consumer's benefit to some extent, and not quite against anyone.