Our ancestors did not own smartphones, so the broad evolution argument is kind of garbage. User interfaces need to be researched before we can make conclusions on skeuomorphism vs "pure digital".
Furthermore, the author talks about affordances and how Metro has none. This is false. Anything that can be touched on the screen reacts to your touch. For example, if you're scrolling down the main menu and your finger happens to press down on a tile, the tile will be "pushed inwards" at the point of contact (even if you haven't released your finger). It's very subtle, but it definitely lets your subconscious know that in the future, if you would want to press that thing, you can. Now it's not an immediate affordance like a door knob, but a touch screen in itself is an affordance for touching, and once you touch then the other affordances reveal themselves.
Furthermore, the author talks about affordances and how Metro has none. This is false. Anything that can be touched on the screen reacts to your touch. For example, if you're scrolling down the main menu and your finger happens to press down on a tile, the tile will be "pushed inwards" at the point of contact (even if you haven't released your finger). It's very subtle, but it definitely lets your subconscious know that in the future, if you would want to press that thing, you can. Now it's not an immediate affordance like a door knob, but a touch screen in itself is an affordance for touching, and once you touch then the other affordances reveal themselves.