This is correct. However, it's important to point out that the .NET native compilation can also target ARM architectures. For native development in C++, one would need to build and distribute ARM-targeted binaries also in order to actually be "universal".
That, in combination with emulation for the x86-based legacy stuff, should be a powerful reason to use the Microsoft platform.
Even if ARM servers don't become a thing, the support of ARM servers only benefits Microsoft and their current "Universal Windows Platform" strategy.