The other aspect is that investing isn't the end of the story. Nearly all car companies have made investments in green energy--but which are likely to produce results and win the market?

Tesla is expected to execute better because it hasn't just set up a department to prototype EVs. Tesla is dedicated to EVs. The company is built on the technology. That results in a lack of legacy distractions, faster iteration cycles, effective vertical integration, and a wholly different culture and brand.

It's a classic startup disrupting incumbent story. It isn't a sure thing, but it's enough to make Tesla very valuable.