You should know that something like half of Model S buyers came from cheaper cars. Same is happening with Model 3. So your market size estimate is wrong.
Which totally made sense, if you wanted an electric car. What was the other option? A Leaf? I suppose this is one of the things that may change over the next few years since there will be other options, even if they come on limited quantities at first. From 2012 on Tesla had a really nice window of opportunity they could use to grow and expand. They were alone. It seems they made some mistakes along the way, especially when it comes to manufacturing. To me it looks like this window is closing faster than most people assumed over the next years. If they manage to grow as fast as they do now (profitably) for the next 3-5 years, fully ramp up the Model Y and Semi, they simply made it and Shorts have been wrong.