I agree that lots of books are garbage too, but they still require some amount of focus and attention, which makes them much, much less bad for brain development than watching TikTok videos all day.
From what I've seen it's either or. It seems the exception that a kid or teenager will watch a healthy mix of both.
I agree that lots of books and long-form content could be summarised, but if you ever read a book than watched the movie adaptation, you can understand that even though there's not necessarily a lot of value being lost, there can be.
Also, I think book reading helps a lot with your attention span and capacity to engage with content for a long time. I think the problem is not assigning books to read to those kids, its assigning the wrong ones. Any kid can get absorbed by a book where they can relate to the characters.
There is an undeniable “holier than thou” attitude pushed by avid book readers. Frankly, there are a lot of books and long-form content which could be summarized without losing value into a single internet blog post. People have changed the way they consume information and books are on the decline but I reject the idea this is a crisis.