Older Daughter wanted a career change so she went back to school for a Teaching Credential a couple of years ago. It was just plain scary trying to help her prepare any sort of computer-based instruction for her own students in a manner that would earn her a fair grade from her own grad-school instructors.
She and her fellow students often couldn't make use of what their professors provided to them. First barrier was the faculty had always lived withing the closed world of Macs and refused to offer any help to PC users who couldn't read the Mac-based online instruction, tests, links to other sources, everything. And the professors couldn't view what these students prepared on their own PC's, or they considered anything non-Mac so alien that it wasn't considered first-rate work.
These Credential-school grad students were mostly recent BA graduates and had used PC's for years, now they were being told to come on campus and use the Mac's in the computer lab if they wanted to earn a good grade.
I helped daughter with several work-arounds (rtf for example) to produce work acceptable to get good grades but it was a PIA.
What I'm getting at is, I doubt that many mid-career elementary school teachers have the expertise or hardware for preparing online coursework, or any concept of making it readable to PC / tablet / phone owners.