Grown women have always been the biggest readers in history and now. Men usually aren't big readers, never have been. I doubt many kids were ever passionate about reading. Most read because they have to in school and boys rarely ever read if it's not mandatory. It's the same with men. Men read way less than women, always have. And when they do read men tend to read nonfiction books, etc. Women read for pleasure more than anyone. Girls do read more than boys it seems but to what extent?
My point is, children are not monolithic. You got some that like to read and some don't, just like adults. When I was a kid, I read a lot. I read way more than I ever did as an adult. Why? Because as a kid I wasn't as busy, and I enjoyed books more back then. As an adult, I am much picker with my reading than I was as a kid so it's harder for me to find books I wanna read. A lot of the books that are popular don't appeal to me and I only read indie now. I haven't bought a trade book in years. But if you asked me would I rather write than read, hell yeah. I spend way more time writing and I enjoy immersing myself in my own stories more than I do reading. Doesn't mean I don't like to read anymore but it's not as big of a passion for me as it was when I was younger.
So, IMO, I don't think kids in general were any more passionate about reading in the past. If you didn't have school, many wouldn't read at all. It's the parents we should be talking about. They should enforce reading more and get their children more involved than just letting them be on the computer on social media all day. But then again the parents probably don't read either so...
If you don't do something you sure aren't gonna tell someone else to do it.
I was a kid in the 80s and a teen in the 90s. We didn't have the Internet, cell phones, social media, etc. All we had was cable, TV, and music. That in itself was enough of a distraction for some kids not to read. And when I was a kid we always went outside to play everyday after school and on weekends. Many kids only read when they had homework. Today, these kids have WAY more distractions than even I had so heck, if I was a child today I don't know if I would be reading much either for pleasure. Not saying that's a good thing at all. I think kids should be reading as much as possible to learn stuff, but much of it is a sign of the times and not so much about the state of literature or books. I don't have kids, but if I did I would definitely instill the importance of reading to them.