Lies
"For months, developers at Facebook and Apple have been trying to figure out a way to continue to allow advertisers to track ad conversions – to understand which ads people click on – in the web's increasingly complicated technical environment."
No, they're not. It is easy to determine which ads people are clicking on. Let's say a company is running five different ads for the same thing and they want to measure whether there is a difference in effectiveness between the presentations. Here's how you do that:
Ad 1: links to https://ispamyou.adnetwork/ad/1
Ad 2: links to https://ispamyou.adnetwork/ad/2
And so on. Or, because the short numbers will get reused:
Ad 1: links to https://ispamyou.adnetwork/ad/aei6zln2
Ad 2: links to https://ispamyou.adnetwork/ad/fl2ozvnp
If you're on something which doesn't do custom paths, you can do the same thing with query parameters. Then you just dump the request in a database to look at later and redirect the user. Facebook could build a server to collect that if there is a user who lacks the technical knowledge to do it themselves. I wouldn't be surprised to hear they already have that. The privacy protection thing doesn't make that harder.
What it does make harder and what Facebook wants to make easy again isn't figuring out what ads people are clicking on, but to figure out who the people are who click on the ads. Or do anything else online. That's what Apple's privacy measure is intended to protect. Facebook and its advertisers are angry about that and I understand why, but that's just too bad. They never asked my permission for invading my privacy. I will neither ask their permission nor care when they object to my blocking and impeding them.