[dewey]

> let's say "InteretDude420" to a real name

For many targeted / personalized ads purposes you don't really care about the real name. You mostly care about linking hardware / software identifiers (IDFA etc.) to some kind of profile that you attached information to (Likes technology, fashion, classical music,...).

If you make 100 separate accounts and open a VR arcade you are probably just filtered out as an anomaly. It's not about having a 100% coverage, it's about having good enough coverage of most users. Just like filter out bot or ad blocker users as there's still enough regular people.