The history on skeuomorphism in visual interfaces you write about is an good one, and would do well to involve some more concrete examples that people might actually remember interacting with, rather than a generic “do” button. The old Apple apps, iCal, Notes, and iBooks are great examples when compared to their modern counterparts.
I find it interesting that you argue that skeuomorphism in voice interfaces will go away. Will it, though? What would replace it? Here’s an interesting piece from Gizmodo on why a completely sans-skeuomorphic world is not only a fool’s errand, but impossible to attain:
Skeuomorphism is not a design crime. It’s the language that human designers have written to let humans talk to machines. That’s not something we should hate.
VUI (Voice User Interfaces) and NUI (Natural User Interfaces, which is a superset of VUI and includes other interfaces such as gesture recognition) are by definition skeuomorphic, so they inherently become less natural and therefore less usable when you remove their skeuomorphic characteristics, do they not?