Of course we do, but for example we use nicknames on Facebook and our government shot down the real name verification they were pushing.
Data privacy acts are actually enforced, and most users are at least somewhat informed about GDPR and their rights.
Meta is not allowed to link facebook and whatsapp user data to get around that, so the data gathered within whatsapp is not nearly as powerful as the connection between the two would be (three, if you count Instagram), etc. etc.