> Seniors don’t use SO anymore

Did they ever? SO wasn't around during my junior days so I never got to experience it from that angle, but it looked like it would have been an incredible resource for those who juniored in its heyday. However, I never found it to be successful in delivering to the problems I encountered as a senior.

Right, SO was always better at answering beginner questions then advanced ones, except if the complex question had a broad appeal. Part of it is because the format is not good for asking a context-heavy question. Another part because you were dependent on the pool of people answering, and the more niched the question was (using a library not very popular, for instance) or the more expertise it required, the less likely you were to find someone.