NikolaTesla

Given the astronomical P/Es of many public high tech companies and the lack of net profit from the latest batch of IPO candidates, has the market turned into a reliance on the greater fool theory instead of rational belief of the underlying company's potential return?

You see it in job posts everywhere: "looking for a full-stack developer, engineer, programmer". What exactly does that mean? And yes, since I'm asking the question, I must not be one. Seriously though, how would you define it?