Now, is it realistic that it will be illegal for EU providers to use services that are owned by US companies? Very unlikely that this will be the precedent (yes, I know, there are cases where some courts deemed Google Analytics and Google Fonts illegal).
However, I would personally also feel more comfortable using services from countries where the government can't subpeona all data at will.
"I'm just a guy who shows up, they hand me some cash, and then I go up on stage and play my guitar. Why do I need to read up on accounting?"
Some software developers are in that state of naïveté about the data they collect about their users.
Even if it's just a blog, it may be collecting and storing data about readers in many different ways: ads, tracking pixels, comment logins, etc.
And even if you don't reside in the EU, you can reasonably believe in privacy and abide by the GDPR.
The EU has ruled, now let them enforce it!