Also, given that the GDPR only applies to people of the EU, I'd say it, at the very least, has something to do with living in Europe, since, umm, y'know, that's where most people with citizenship in an EU county live.
US company using Paypal to accept money from US persons? Paypal has presence in the EU and will hand your money over.
Really, it even has nothing to do with residency. It's all to do with jurisdiction, when Elon happens to be within EU jurisdiction he is protected by the GDPR.
When Elon takes his jet to visit Greece, he is indeed protected by the GDPR (even if just interacting with US based companies while he's on holiday, GDPR still applies)