[Nick Zwar]

I suppose it greatly depends on how you define “Montage”, obviously, just about every every movie (except perhaps Hitchcock’s ROPE or Sam Mendes’ 1917) is an edited montage made up of different scenes. Now I’m not saying every edited scene is automatically a “Montage” (or you wouldn’t need the term separate from simply “editing”), but the thing is that not everyone defines what a Montage in a movie is the same.
Back in the day, what Eisenstein pioneered was the idea that seemingly unrelated scenes and images can be edited together to create the impression of something else. However, this concept, as you point out, has basically become one of the “basics” of film making, and to differentiate what some may view a “Montage” as what others might see as mere “editing” are fluent to say the least.
I think the training scenes in the ROCKY movies are often perfect examples of elaborate montages that fuse into one scene.
Like, for example, this slick 80s Montage from ROCKY 4 with the pulsating synthesizer driven music. It’s a perfect “Montage” in the sense that the edited scenes don’t have a clear continuity, nor are they scenes from the same time or space, but could have happened at various different times before the fight, yet they fuse into one kinetic and very effectively edited Montage.