Having founded and flopped on 2 voice-based startups (sonictrade & verbl) I can attest to the difficulty getting user adoption and the importance of being really, really good at simple, but useful tasks. If Alexa gets the plug pulled it won't be because of a small userbase, but rather failure to stop annoying the userbase with recommendations...something Siri does well. And Siri on the Apple Watch is absolutely killer. It is the ultimate functionality on a wearable device, with voice search being the best utility. Command-based voice AI is still in its infancy. The ability to summon cars, book flights, trade stocks, donante funds, turn on the lights, bet on sports, etc. all are doable now and improving in quality of execution daily. But 15,000 engineers working on Alexa? That's where your $10B went!