The difference is that Airbus didn't as much build new factories (and certainly not several at the same time) as it is a consortium (and later a unified company) of formerly independent European aerospace companies. E. g. their current German plants, Hamburg (commercial aircraft) and Donauwörth (helicopters) used to belong to MBB (https://en.wikipedia.org/wiki/Messerschmitt-B%C3%B6lkow-Bloh...) and then DASA (https://en.wikipedia.org/wiki/DASA). That's a consolidation similar to what happened in the US, albeit maybe with more "state interference".

I read something once about the question of Airbus and Boeing subsidies. The short answer was “It’s complicated.”

Of course, that particular question seems to have been rendered irrelevant by Boeing’s quality crisis.

And also kinda required from an economies-of-scale point of view. The US is spoilt by havbing a massive, culturally-and-language homogenous country. Despite their wealth, If you want to hit those scales in Europe you need many countries on your customer list. And since each country (usually) has it's own language, laws, norms, sometimes currency, it gets way complicated, way fast.