Do not get me wrong, I like electric cars and what Tesla has done with all the tech around it.
I said something different: the problem is not competition but too much competition, and in this case your chance of success is smaller. I do not think Tesla is going to disappear in the near future but they are facing challenges.
I do not see a turnover in this case : when you have passionate people who were present at the start , allowed to develop technologies that made Tesla what it is now and those people left within a small interval of time, it means in general something has been broken and/or people do not want to continue in the way that it is handled.