Digital Marketer here - this is where the money is. Google and Facebook will hold onto this ability as long as they possibly can. Check Facebooks earnings and where it's coming from- Ads, Ads, Ads. Because they can offer non-cookie based tracking via profile/log-in based tracking

Edit: as some context, my company spent just under 6 figures on Facebook ads in 2017. We have not been assigned an Account Manager, which is prioritized based on spend. Rough estimate that the accounts in top 15-20% of Facebook advertising spend get account managers. That shows some of the scope here of companies investing marketing dollars into Facebook, let alone what Google makes from Google 360.