low taxes, lax regulations, massive tax break

I call complete and utter bs. If taxes where a reason, Silicon Valley would be on Virgin Islands.

Ireland and Malta are the countries most overseas tech companies (and gambling and porn companies) choose as their European seat, not because they have an amazing amount of great skilled talent, but because they have really low taxes and regulations.

And this proves your view being overly simplistic and unconnected to the real world. They chose to settle their profits in these countries, not their development.

Also, the EU really doesn’t want companies that are so big and important that they are more powerful than the government.

Dude, holy shit. You're confusing the EU with China.

Lastly, another issue is that the EU, when handing out money to companies, prefers the Airbus model. Instead of concentrating everything into one city, like in Shenzhen or Silicon Valley, they like to spread everything out over all of Europe.

That's at least an interesting thought but probably neglectable in the bigger picture.

The real reason is, that you need talent and you can attract global talent with the global highest pay. US was rich before, so global talent naturally gravitated towards it. Furthermore and probably foremost, the US were decades ahead of most countries after WWII. It is no suprise that computerization happened there first and that subsequent business models like private operating systems could develop there first, as a very result of that. Everything boils down to the trajectories of the war.