From Mitchell himself - at the very least they are growing very quickly. For all the complaining about "pricing pages", I think hashicorp is doing the right thing. Focus on selling to the big dogs who can give you a sustainable business and don't cloud your pipeline with smaller shops who wish to shop around.
Hashi should honestly set up a donations page, we'd love to throw them some money because we use their entire suite, but the pricing is clearly geared towards whales.
The only source I found was https://www.hashicorp.com/blog/2017-year-in-review which just says the company "can be successful", not that it is making money.