I agree with your assessment, based on my limited experience. I'm a fan of Alexa, I even bought a couple as gifts within the last year, but last weekend I saw a bilingual 30 year-old (with a PhD from UChicago) struggling to get it to play a song. He had a song playing on his mobile phone and wanted Alexa to either continue playing that same song or play any song by that artist. It was a bit comical to watch; OK G had no problem understanding him.

It looks like voice will be one of the next big things, but calling Alexa the winner is a bit premature in my opinion