That's largely analogous to what people attempt to do with virtualisation, but the ability of things to have unpredictable resizing and reflow behaviours throws

That's largely analogous to what people attempt to do with virtualisation, but the ability of things to have unpredictable resizing and reflow behaviours throws a few spanners into the works. My understanding that (at least until recently, things might be different now) is that most game engine optimisations depend on being able to make a lot of assumptions that usually hold true, or being able to calculate most of your scene graph optimisations during a build step.