FATCA was designed to apply to non-US entities it provides clear definitions and channels on what to do and who do you work with, the GDPR has no functional models for non-EU entities.
And again FATCA and SOX applies to huge financial institutions that can afford all the lawyers in the world.
Say I make guitar picks and tuning forks in Zimbabwe I sell it online and I have costumers in the EU. I either need to comply with the GDPR which will be prohibitively expensive or will have to stop selling to EU customers.
The problem with the GDPR is that people don't understand both the inconsistency and the scope of it. Come 25th of May I'm sending a data access request letter to my dry cleaner which they will have to comply with within 30 days or face fines.