Years ago, when I prototyped an orders-of-magnitude physical-properties playground web app, I found the development bottleneck was searching for video clips and images. For example, find clips showing the heartbeat of a {goldfish,mouse,cat,dog,child,adult,horse,elephant,whale}, for a <kg - body mass - metabolic/heart rate> association (metabolic rate scales with body mass). Jiggling an oom kg scale, maybe you're shown a cat or mouse, and maybe a mouse heart patter, and whale's slow swish. Providing a massive (sorry) hidden curriculum. They all exist on youtube, and might be fair use for OER content, but finding them was not plausible. And still isn't, even with commercial use of stock videos.

In the 1950's, the first Powers of Ten zoom book was hand drawn from books over years. Around 1980, a PoT film and book could use photos, but still good people made mistakes. Now creating a PoT zoom book can be homework. A video a school project. An XR a professional project. Technology, media search, acquisition, and handling costs, throttles science education content.

Necessary but not sufficient, of course. The first book might have been imagined and created earlier, but wasn't. 1950's astronomy textbooks needn't have had the color of the Sun wrong, and the same now in 2020. Though, anticipated difficulty of creation does throttle imagination...

If OP search were deployed on youtube, and fair use in its current form was allowed to survive, providing a historical step-change in the abundance and accessibility of reusable content, how might you imagine using that?