And at least right now, investors seem to think that Tesla will become wildly successful eventually. Will that actually happen? Who knows.
In my opinion that's a very small bit that can't possible justify the current price. If I was going to justify investing Tesla today I would have to make the case to myself that my ROI on Tesla would be better then my other possible ROI I could get else where. Let's say I am hoping for a very reasonable 6.5% return, based on rule of 72 I would expect the value to double in ~ 11 years. Assuming Ford grows at a similar rate over the next eleven years Tesla would have 4x the market cap as Ford currently does. I just don't see how you could expect to invest at the current levels and expect a reasonable return. Even if Tesla perfectly executes for the next 11 years there is no way it would be worth it's current evaluation let alone have room for a decent ROI.
They would have to get 60X bigger in terms of output to get where Ford already is and has been for a long time.
Do people really think that Tesla will grow 120x larger with 100% probability? Or 240x larger with 50% possibility? That seems irrational to me.