They haven't gotten deeply into it because it really isn't about Donna or Eric or Hyde, the original characters are now background characters. Think about your childhood friends. How many of them are involved in the lives of your children? Of course it didn't occur to me that midge was even missing because my family is full of selfish, distant people who have little to do with each other. But the disappearance of Hyde doesn't need to be explained. They grew up, they grew apart. Also, in the 90s parents didn't involve children in the details of anything. They didn't think we needed to know or could process things like that. My main complaint with season 2 of that 90s show is when one of the girls says something about fighting the patriarchy. Teen girls didn't care about or talk about those things in the 90s. We cared about boy bands and jtt and Devon sawa and... Boys. Just boys and cucumber melon scented everything and low rise wide leg jeans and necklaces with blown glass mushrooms and ck one. I don't think I ever heard the word patriarchy until I was in my late 20s.