Pretty much what my reaction was when I skimmed the paper. I left the page amused about how can someone measure degree of self-enhancement? It's not something like having a consensus that boiling point of water is 100 degree celsius at 1 atm.
I am inclined to agree with you on your second point-reading non-fiction non-linearly. Also, what makes us feel guilty about the pile of unread/unfinished books is when we subscribe to 'number of books/period of time,' read as a metric.
If I have to add anything, I would say that an unsophisticated reader does not stand by the metric of counting the number of books he reads in a year.
It's also important to note that not all medieval and historic structures survived the test of time. A case of Survival-Bias. As the utility requirements of the structure may change over time,there is no incentive for engineers and clients to design a structure that would last more than 50-100 years. As far as the current building design provisions and policies go by, rebar does it's job.
What needs intervention is to find a suitable replacement for concrete/cement citing it's increasing contribution to global warming.
This is profound and exactly what Jiddu Krishnamurti often talks about. When you do put a word to that emotion i.e., sad, angry, happy etc., you no longer suffer it. What's left is just the joy of life.
The world problems however needs all the specialists and generalists. And instead of taking generalists too far, a specialist with minimum knowledge and experience in few other contrasting domains is good enough for him to get creative, draw analogies and solve problems.