I could actually see it going the other way: voice assistants becoming more human-like. AIs from familiar sources like the game Portal (GlaDOS), the movie Iron Man (Jarvis) and the real world (SmarterChild) are often injected with personality traits that look terrible for a bot on paper (sarcasm, passive aggression, emotional sensitivity to input) but make them much more “human” and relatable as a result. Current bot solutions are a bit of a half measure by comparison (hobbled by available technology as well, no doubt).
The functional issue with dynamic interfaces is they have to give some feedback to user prompts, and in a voice interface that feedback has to be a voice. Humans are the only thing in our universe that have voices (that we know of at least) so we are the zero point for any related design; I’m not sure de-skeuomorphisation is even possible here?