When was the last time you heard about a European cellphone manufacturer, or social media network, or web browser being acquired by an American monopoly?

I can only think of Nokia, purchased by microsoft in 2014. Those phones ran windows CE before that even, so you could hardly have avoided the american tech industry.

All I'm trying to say is, it's impossible for Europeans to both A) be on the internet and B) avoid the US tech industry.

In the EU there is the threat of jail time if a user of your service does something bad and you haven't completed the necessary bureaucracy to be immune to it. This is the opposite of the US. See for example pissmail.

Nokia phones ran mostly on SymbianOS

Sorry, I stand corrected