I'm no Musk fan with his latest comments, but I disagree with this quite strongly.
Have a look at how many vehicles Toyota have produced for the last 10 years, and have a look at their stock price. Take a guess at their stock price in 10 more years. It's a flat line
Now have a look at the number of vehicles Tesla have produced in the last ten years. Now guess at their stock price in 10 more years.
There is a chance Tesla will make 20 million vehicles by 2030. If they do, their stock price will go up a lot. There really is not much chance of Toyota doing that. (they're not trying to)