Even older aircraft like the F-16 and F-15 have many modal UIs. They also have a lot of UI features that were added on over the decades which make the system much tighter to sit in than the original pilots would have experienced. The big difference between them and an F-35 (or even F-22) is that the newer ones have the opportunity to clean up or unify a lot of those UI systems so it feels less ad hoc (at present, give it 30 years).
The modals are usually for things you're not going to use often (comparatively), or are very low "depth" menu for modes that have major impacts on what you're doing (so you're essentially selecting activity type)
