It's all relative to your environment. A senior developer in one shop might be one of the more junior guys in the next shop. Salaries also vary depending on the market rates for the stack. To me, deciding on whether someone's a Senior Developer depends on few things: 1) How much experience do they have in a stack similar to mine? 2) How much of their time would be spent learning versus doing? 3) How much of their tim…
I don't really see what teaching has to do with it. Not every developer's goal is to teach. The idea that he most capable developers should give up doing to pursue teaching is not very good economics. This assumes that the optimum balance is to have a well normalized force of average developers. In reality, you need extreme outlier doers. It's only because management is not optimizing for value creation that teaching is valued. They want a large growing number of average subordinates, not a fixed amount of commandos.