It’s also seriously funny that it’s the same accounts that argue this stuff every time it comes up on this site. ;P
People do this all the time, there's native mobile applications using the true platform frameworks for both operating systems
There's plenty of abstractions for Win32, too, such as Qt (see VLC for example, which feels native to Windows).
The only major consumer program written in WPF I know is Visual Studio, but I haven't heard of WPF development in a long time (except for the move to open source).
Qt is harder to create bindings for since it’s C++, meaning it’s more likely that your language of choice doesn’t have bindings, in which case if said language doesn’t have C++ interop you’re stuck.
Or write it in Win32 api, in C.
For GNU/Linux, write it in GTK or QT, as appropriate.