Native GTK is not the Apple problem. GTK developers could use Mac application paradigms instead of Windows's and embrace GNUStep/Objective C for GIMP and GNOME

Native GTK is not the Apple problem. GTK developers could use Mac application paradigms instead of Windows's and embrace GNUStep/Objective C for GIMP and GNOME instead of implementing their own toolkit. They made the choice of going Windows-like way, not Apple. That's the reason of why "on Windows for years, but still tricky on MacOSX".