What does "scale"even mean in UI context? 10 or 100 controls in app makes difference how exactly? Retained apps redraw when needed, they are idle most of the times. How redrawing every frame helps to scale?
This thread (and post) keeps mistaking immediate mode GUIs with declarative UIs. You can have declarative UIs that aren't immediate: the vast majority of them are, and they are idle most of the time.