I think quite the opposite happened, just not on X11 level. The web browser is essentially a thin client nowadays. The fact that you have full client-side scrip

I think quite the opposite happened, just not on X11 level. The web browser is essentially a thin client nowadays. The fact that you have full client-side scripting is one thing that was IMHO a bit underdeveloped in classical thin-client systems because with that you can mask network latency much easier (though, admitted, I don't know a lot about how X11 handles this).