I used to work in higher ed. The reason you don't see this is that it's harder to produce (usably) than an eli5; there is little incentive as there aren't many

I used to work in higher ed. The reason you don't see this is that it's harder to produce (usably) than an eli5; there is little incentive as there aren't many advanced enough to want it who aren't also in walled off training; and there are often many tiers between layperson and professional such that connecting the right audience with the right material is its own problem. I agree it is terribly frustrating.