You are aware that this does not make sense, since to do business with people from other countries you already have to comply with their laws in terms of taxes and accounting anyway.

Selling to EU customers as US business already requires you to have a VAT ID in EU, so what does this change for you? In the end the main provision is to only require and store customer data which is effectively needed for providing the services and goods you offer. If you are doing business responsibly, this should not affect you at large as it mainly formalises these processes and requires you to actually write down and document what data you need for what processing steps. If you can not do that, your business is already flawed and not because GDPR does not work for you.