If there were demand for education there would be a black market for educators. The fact universities can get away with being non-educational institutions is proof of the lack of demand.
Was there demand in the past? As per the recent post, meaningful literacy is limited to around 2% of the population. Perhaps this cohort demanded education, once upon a time.
However, we can look at China as an example. China has never had demand for education. There is demand for passing mandarin tests, which is orthogonal.
I suspect that to the extent education was ever demanded, the demand was artificial. Essentially the same as the artificial demand for credentials today, but slightly superior in details. There was a demand for power, and to the extent the educated held power, they could demand education by proxy. Simply because you would look so dumb compared to the other courtiers if you didn't have it.
On the surface, education is a purely subjective good. The only person who cares if you're educated is someone else educated, and even then only if they're educated in the same school. (Real school, in stark contrast to a Prussian school.) The link between education and any profound benefits is invisible to anyone who isn't themselves educated. (E.g. philosophers know better than to attempt to be kings. To the non-educated this looks like being weird, not wise. Obstinate, not observant.)
Unless you're already educated, education appears to offer no advantages. You can't even see the social benefits, as in folk who would like you more, because the educated and ignorant look the same.