If they have headquarters outside the EU, and only use data they've already acquired/processed to make money off of EU consumers from outside the EU, GDPR shouldn't be an issue for them in the same way.
And GDPR makes it harder for their competitors to catch up because it's harder for those competitors to get data.
It could be that the EU would block them if they wanted to host fb/etc... including ads, and didn't have a presence in the EU, but I'm not sure if that's the case.