I think you are right, it is because of the US tech companies being much more successful.
BUT, I don't think it is because of the scale of the US market. As others have pointed out, Spotify from Sweden and many companies from Israel are also very successful.
I believe the real underlying reason is the strong VC ecosystem, which was established decades earlier in the US has led to the success of the tech companies there. In mainland Europe, VC is just getting started. My bet is, that we will see similar companies in 10-20 years from now.
For what its worth, I have seen comments almost exactly like this 10 years ago on HN. It its very hard to predict when a real culture shift like that will happen. (I agree its an important part of the puzzle)
BUT, I don't think it is because of the scale of the US market. As others have pointed out, Spotify from Sweden and many companies from Israel are also very successful.
I believe the real underlying reason is the strong VC ecosystem, which was established decades earlier in the US has led to the success of the tech companies there. In mainland Europe, VC is just getting started. My bet is, that we will see similar companies in 10-20 years from now.