> a key facet of a "diagnosed" disorder tends to be whether or not it (negatively) affects your life.
Which also brings us to an important point that is totally missed in the article and most of the discussion imo: maybe one of the (many) things that have changed is that lives are more negatively affected by stuff nowadays (or more reported to be so). We live in increasingly complex societies, we have to socialise with more and more people and navigate more demanding and fluid social dynamics. Traits that can be advantageous in a certain context can be disadvantageous in another (and affect one's life negatively).
As the guy said, if you think you hear voices but they tell you to go to sleep on time and do a good job at work, you probably don't need treatment.