i don’t know the exact reason, i don’t work for epic nor i have studied the internals. but afaik:
it’s called “vendor lock-in”.
and ms is more to blame than epic imho.
one of the reason some people dislike ms, (google does something similar to make android unforkable).
for a software to run on windows with the highest compatibility you are forced to use the ms compiler (msvc). which is distributed only with vstudio (afaik).
that’s one of the reasons you can’t cross compile to windows from linux (since it’d be illegal to distribute the sdk headers (afaik)).
(but you can still cross compile from win to lin because the penguin is cool).
something similar happens with DirectX, ms platform require DX most of the time, and DX is not available for other platforms. Luckly Vulkan exists to fill that gap sometimes.
it’d be nice if ue could use clang on windows, as it does on linux. some effort has been done, but i don’t think is officially supported.
if you were to try to compile on mac, iirc you’d be equally forced to use xcode. and the last version of xcode, and the last version of xcode forces you to have one of the last versions of the hardware. which is particularly insidious.
i’ve worked in projects where we had to upgrade the hardware to keep working on a project due to that.
having said that, you can still use rider (which is free for non commercial use), alongside vstudio (without having to open it) which is what i do.
lol ms has a section on wikipedia specifically for vendor lock-in (though i think it lacks other cases) Criticism of Microsoft - Wikipedia