Props to the author for taking the time to share their PKMS. I respect anybody who goes this in-depth to discuss how they go about learning.
What didn't resonate with me from this article is the need to retain a large amount of information beyond the main points of a book or article. Isn't that what the point of the PKMS is?
I like to think of reading as creating indices to core concepts. If I'm working on a problem, and it reminds me of a concept I read in a book, then that's a win. Add tags and there is no reason why you can't quickly rediscover any concept you've previously come across
Usually my notes are the parts that distilled the book to the main, useful points.
My mental storage is limited. I'll let the technology worry about storing knowledge, so I can worry about executing on it.