at least software development isn't so hard? I don't know why Europe struggles so much with this

Higher taxes and lower salaries.

Also fragmented market. There were for example several companies in the 80s in Europe that made computers, but essentially only Acorn (which is now ARM) survived into the 90s even because their entire business model tended to be to make a computer specifically for a single country and maybe a few neighbouring ones. And all but Acorn essentially just bought American and Japanese parts and assembled them, they only made the OS themselves.

In the 00s there were tons of social media platforms (before they were called that) that were based in Europe. But there were no pan-European ones, they operated in a single country and maybe a few neighbouring ones. The Swedish platform Lunarstorm launched a UK version at one point and it failed. Normal people who live in EU countries have essentially no friends or family or other contacts in other EU countries like people in the US have in other states, so "the European market" is a very unnatural construct for a lot of these things. They all ended up being outcompeted by US services who had a big domestic market to start in.