Relevant video: https://youtu.be/4X9ww6FtUhE?si=R5TCNF0lTho9kHWp

Tl;dw is that sure, the US could withhold software updates and sure, NL could do their own software thing, but there is a whole intelligence software thing too that makes it harder. And ultimately if the US stops supplying new parts the existing planes are quickly dead in the water anyway. So it’s a short-term solution at best.