Arguably, until recently there just wasn't any reason to: Europeans were happy buying American software and online services; Americans were happy buying German cars and pharmaceuticals.
Personally, I don't think the US clouds win anything on merit.
It's hard/pointless to motivate engineers to use other options and their significance doesn't grow since Engineers won't blog that much about them to show their expertise, etc. Certification and experience with a provider with 10%-80% market share is a future employment reason to put up with a lot of trash, and the amount of help to work around that trash that has made it into places like ChatGPT is mindboggling.