The cost of producing a large amount of well-thought out, cohesive, modular, high-visual-quality video is in the labor, not the cost of the tech. What the professor is saying is that she doesn't have the time to write 200 hours of script (or even write out 200 hours worth of detailed notes), record the 200 hours (which'll take more than that to record - no-one can do 200 hours of high-quality video on the first take), go back and edit stuff (even just cutting out uhms & ahs takes long than you think - step 1 will be to re-watch the 200 hours of video to find them
The $100,000 figure struck me as being weird, as well, but the professor's point is that producing 10 hours of video for each of 20 lessons in addition to all the other course materials is way, way too much to just demand that someone do.
Besides, for stuff like this you mostly want a good book anyways. Something that you can read a short paragraph of, stop and think about for a bit, come back and re-read in order to make sure that you got it, read another paragraph the same way, maybe work through a problem or two. Videos of this would be nice, but they're window-dressing around the main event.