I personally think the mentality is stupid and probably quite inefficient. In my field, law, they don't even let you into the courtroom until you're 5+ years in. Practicing law is an art and people with 20 years of experience are just better at it than people starting out. I never understood why so many people think software development is any different. Companies don't lay off their lawyers and hire fresh graduates when some new major new law goes into effect, so why do people lay off their software developers and hire fresh graduates when some major new technology becomes popular?