How much can our heads hold?

My husband comments on how well his dad remembers names, people, places from his childhood. 
I said it's probably because he doesn't have all the technologies we do to clutter his mind.
I forget a lot of things, but I do remember a day when I could concentrate.
I'd fly right through one book after another.
These days, I'm used to  processing lots of short bits of info, scrolling, ya know, but it's hard to stick with longer stuff.
I wonder where all this is leading.
Will people lose the ability to think deeply and carefully about matters?
Are we losing our marbles!?

My head feels like this tonight.