I fully agree with you, that tesla is waaay to overvalued now. But so are most of the stock markets now. Im quite negative about their current statistics, however not their revenue.

Their revenue has 5 fold in the past three years. That is what people are speculating on that tesla will keep growing.

We need to keep in mind, great companies like Amazon, had a long period of losses too. So investing in Tesla is risky, however this is one of companies that could pay off a lot.