This essay is nothing more than the authors opinion (which there is nothing wrong with) presented as fact (completely take umbrage with this). Looking at the authors website, the current design of Apple's UI elements are not to their taste. An example would be this; http://www.nicholaswindsorhoward.com/blog-directory/2016/1/2... The odd idea is interesting, but it's massively regressive.
Yeah. It's particularly annoying how he notes in passing that since 2013 "almost all software designers, including Apple’s" have started to prefer the flat style, and yet he still presents his own opinion as objectively correct.