It depends on where you draw the line between what you call a webpage vs a webapp. If a webpage is something with just text, images, and non-interactive forms (and audio and video to a lesser extent), then it's perfectly possible.

Nobody complains that Google Maps are using JS. People are complaining that developers abusing JS just to show simple page or video which is perfectly doable with HTML 5.

Showing a simple video isn't simple without JS, it's just clunky in all aspects.

It's very simple: just use <video> tag.

I think you're mistaking simple for something else. Simple can easily be clunky. I would even say simple is often clunky.

Making something elegant, and full of features, and pretty is often complex.

It's not simple even for the developer to use the video tag if you want a thing that works.