As he just found out, that's exactly what the EU can do. And as he's about to find out, the EU is way too important a market for the American economy to ignore or pull out of.
Play on your neighbour's yard, obey their rules.
The EU can certainly do a lot, with the exception of producing their own major tech companies.
I think rather, that it is the EU who cannot live without US cloud services and AI-services. Imagine if the US, behind closed doors of course, threatened to cut off all cloud services. Huge parts of the public and private sector could collapse.