It's also an interesting case study. Alexa foundationally never changed. Whereas OpenAI is a deeply invested, basically skunkworks, project with backers that were willing to sink significant cash into before seeing any returns, Alexa got stuck on a type of tech that 'seemed like' AI but never fundamentally innovated. Instead the sunk cost went to monetizing it ASAP. Amazon was also willing to sink cash before seeing returns, but they sunk it into very different areas...
It reminds me of that dinner scene in Social Network. Where Justin Timberlake says "you know what's f'ing cool, a billion dollars" where he lectures Zuck on not messing up with the party before you know what it is yet. Alexa / Amazon did a classic business play. Microsoft / OpenAI were just willing to figure it all out after the disruption happened where they held all the cards.