possibly, but videogames have been doing layout for ages without CSS and they can vary a lot from game to game while most desktop applications have basically the same 2-3 layouts: input and edit some text, fill in some form, display some data in a table, a tree or a chart
Just to be clear: when you name niche desktop applications you are literally saying that they are not "most of them"
BTW all of those applications you mentioned use many of the same techniques video games use (for the same reason: custom layouts), existed long before the web and are doing just fine without CSS
> Document readers lay out every possible document.
you mean like vector graphic software, DTPs, word processors etc etc?
Flash did resolution independent graphics and layouts on the web back in the late '90s, we killed it - not without reasons - but we still haven't created a decent alternative to it
