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.