So... your 'argument' is that VNC-like stuff is 'good enough', even though it is clearly much worse than glyph-by-glyph stuff for the vast majority of windows that anyone ever opens using any windowing system -- those windows filled with text? (Discounting, for these purposes, games and video playback, which clearly should be local or use a video compression algorithm of some sort.)
Almost every use case (save only the GIMP, Inkscape and their ilk) can be covered by video compression or glyph-by-glyph stuff. VNC is bad for *both* of these. As far as I can tell, VNC is far suboptimal for *everything*.