So for Germany (only the federal government, states would be in addition to that) license fees are currently about 500 million € a year, only for microsoft licenses.
For the federal states i only know of schleswig-holstein who saved on 16 million license fees by switching to OSS.
So just by these numbers (no guarantees, i am definitely missing something) it might take a while for europe. Still would be nice if some orange couldn’t turn off our government by pressing a button.
That is a much more detailed view. Thank you.