If you write software using GTK, Qt, or FLTK then you are writing Wayland software.
The majority of Linux desktops are Wayland at this point. Nobody writes software for them?
The Steamdeck uses gamescope which is Wayland. GNOME, COSMIC, Budgie, Niri, and Hyprland are not just Wayland but Wayland only. KDE will be Wayland only soon. Cinnamon is switching to Wayland. XFCE is writing a Wayland compositor.
What percentage of Linux desktop users are not using one of the above? 10 at most?