It’s because technology is harming our brains.
I sympathize with the author and feel this to an extent, but maybe this has more to do with aging than it does using apps and addictive social media. Memorization is a lot easier when you're young versus when you're older.
Though I'm sure it does play a part--spending most of your time on social media leads to not using some parts of your brain. You've got to use it to keep it working properly, just like muscle.