Yeah, when I was young you never got exposed to the idea that there were options beyond disposable towels and tampons (overall, I would say education on menstrual stuff I got was lacking - most of the useful things I learnt about how it actually works, beyond blood comes out of you and it can hurt, I learnt in a book I got when I was 19).
I don’t know if part of it is that reusables and cups seem to be made by smaller businesses, rather than the massive companies who make the other products. Like in school I remember getting given a pack with various samples in and leaflets and it was sponsored by Bodyform or someone - I think they produced the leaflets, so it was hardly unbiased information.
It surprises me that reusables aren’t pushed more from the environmental/waste-reducing angle. My local council does a scheme where they give parents a lot of money off incentives to use reusable nappies, it would be quite cool if they could do something like that but with money off reusable sanitary pads (as the initial investment in them can be off putting/prohibitive for some).