You're right that is a real loss. Really, an Alexa that didn't require a personalized amazon account could still be huge if they could figure out how not to have to justify the costs of running the servers. I think that unwillingness to let Alexa be just a voice assistant is the key roadblock. In a similar vein, Alexa for business could have been a really big deal too if they could have worked it out a bit faster but now I think interest has mostly died out before it had a chance to be adopted.
I'm not a huge fan of the company and I think it's a coin flip as to whether they would just completely screw it up, but I wonder what would have happened if someone like Crestron had taken a real interest instead of just half-assing an integration.