Much of the Windows compatibility is "just" stable API for Windows controls, GUI event handling loops, 3D graphics and sound (DirectX). Linux has stable API for files and sockets (POSIX), but that's all.
And I am saying you don't need to rely on any of that. You can just ship it yourself (statically link, or use LD_LIBRARY_PATH). That's what Windows applications that rely on GTK or Qt do as well, and it works fine, which works well, and it works fine for Linux too. The basics (libc, libX, etc.) are stable, and the Linux kernel is stable.
And this is what Windows does too really, with MSVC and dotnet and whatnot redistributables. It's just that these things are typically included in the application if you need it.
It's really not that different aside from "Python vs. Ruby"-type-differences, which are are meaningful differences, but also actually aren't all that important.
Stop spreading FUD, X and OpenGL have maintained stable ABIs. There is Wayland now but even that comes with Xwayland doe maintain compat.
Sound is a bit more rocky but there are compatibility shims for OSS and alsa for newer audio architectures.
Stop claiming that I'm spreading FUD and show me at least one Linux app which was compiled to the binary code in 1996 and exactly that binary code still runs under modern Linux desktop environment and has similar visual style to the rest of builtin apps.
Got no counterexamples? Then it's not FUD at all, rather a pure truth.
Available API means the whole stack, everything needed to write applications end to end, regardless of their purppose, not CLI and daemons.