A lot of people here are focusing on ADHD, but I think the author is commenting on a different phenomenon, because they were able to concentrate before and now it's just much harder. I feel it and many people I talk to feel it as well.

It's difficult for me to separate whether this is a result of other changes in my life over time or simply a reflex of ageing in general, though I do think it's a wider societal shift. In the same way that older people find it difficult to watch newer movies (and vice-versa), there is a certain pace associated with culture as well. We have, on average, shifted from books to TikTok in the span of a generation.