Are you also going to switch your end user devices, or are you going to remain reliant on Google, Apple and Microsoft? The data flows through those.
Do other institutions care? Some people and some institutions do, but how many?
What about the private sector? Even if you moved all government services entirely away from the US, your economy can still be reliant on American suppliers and communications between the government and the private sector and individuals will too.
> we would switch to sovereign clouds in a heartbeat if we had any good ones in Europe.
What is wrong with the options you have in Europe? That comment suggests to me you do not care enough to do anything that takes effort.