I think it's worth thinking about ways in which new media formats are or are not different from old ones, and how that might offer new ways to ruin the youth. For example, comic books cost money, so you're naturally limited in how many you can buy. 1940s through 2000s - era TV/video games require you to be in front of a TV, vs having a handheld device which is accessible 24/7 regardless of where you are.
The thing preventing brain rot was the uncoordinated, decentralized nature of radio and TV stations. Once TV and radio became monopolies that could provide a unified message, the brain rot set in.
Why do you believe that the social media companies who are monopolies won't wind up the same?
[0] The internet tells me that most American kids have mobile phones by age 7.