I'm not so cynical, in large part because I think you could develop an Alexa skill right now that does most of what I described. However, that is besides the p

I'm not so cynical, in large part because I think you could develop an Alexa skill right now that does most of what I described. However, that is besides the point. This was just an illustration of what is possible if your VPA is a preference-aware negotiation agent. Of course you are free to choose a closed platform, but it doesn't have to be that way.