Are you suggesting that anything about the internet hasn't reduced attention spans?

Especially as it's becoming more accessible and common for younger people to get more exposure during key points in brain development.

It goes beyond simple accessibility and engagement, if young people are not participating in these social medias it can become harder to connect with your peers - so you're almost socially punished for not embracing and participating in brain rot (all social media, not just Tik Tok).