Basically the title.
I have seen the EU-OS/Suse discussions for some months now. However, Ubuntu/Arch/Fedora are extremely mature projects. So competing against them will be hard.
I want to know how realistic the scenario (described by the question) is.
You wonder though, with the big players, whether they can lobby / pay off trump in some way to not be affected? I mean look at how the China tariffs changed overnight to not include mobile phones etc. Can’t have the majority of Apple’s production being subject to tariffs (they sure can’t make them in the US for the same cost)!