I'd argue there's a big difference between companies with positive gross margins and companies with negative gross margins, though both may be making losses in

I'd argue there's a big difference between companies with positive gross margins and companies with negative gross margins, though both may be making losses in total. Amazon most certainly has positive gross margins - and instead chooses to reinvest profits aggressively. Tesla is less certain, but I think a far cry from some of the unicorns that continue to run on deeply negative gross margins with the expectation that scale/future tech/vague fantasies will save them. On the other hand many unicorns don't currently have business models where they are selling dollars for more-than-a-dollar.