You might want to give some sources for that claim.
This article from Time summarizes quite well my view of the issues related to attention span. This is certainly not limited to the likes of tiktok or twitter, but I think those can be considered as representing two of the worst platform formats for meaningful content.
This article at bbc references the time as misguided.
This article shows that measuring attention spans is not that easy and our world is more distracting. Not a good think but it does not blame the people.
This Booktuber got some sources and a nice way of presenting it.
One might argue I am splitting hairs and I do not blame you if you think that. I hope some people think harder about their focus and how to find some calm moments. Yet I say that while searching up sources because I got a mobile notification.