When Apple removes third-party tracking (the IDFA story) and racking across devices, it only helps marketers. It also helps small businesses as well.
Removing FB's ability to track users across their devices through a single identifier (this gets a lot more technical), it only hurts those with the ability to track users and their habits across a wide device set.
It does not stop marketers from writing great copy which converts, great ads which promise to solve for the customer, nor does it help marketers who have a valid reason to reach out to customers from reaching out to them.
It could be argued that it hurts businesses from reaching the right set of demographics, the right age group or any other interest areas the marketer would want to target. It would therefore necessitate that marketers cast a wider net and therefore would be expensive relative to the past.
I argue that if nobody* can target in minute segments, then budgets for marketers with deeper pockets would also be widely cast and therefore reduce their impact, which would lead to lesser spend per eyeball, which in turn would let marketers with not-so-deeper pockets would access the same wider market cheaply.
This would lead to a world where "copy" matters more than programmatic targeting, to some degree.
Focus on copy, focus on building an audience and focus on delivering great results. Nothing cna beat these in the long run. The rest of it is minor drama, which does not affect 98%(+) of marketers or businesses.
*I am sure that FB, just like Google, will find a way around it. Even if that certain way will not be as good as targeting was in the past.
+ number I pulled from the rear-end but you get the point.