There's some truth in your statement that most people do not wish to admit and are quick to dismiss as "rebellious, arrogant juniors". I generally see two kind

There's some truth in your statement that most people do not wish to admit and are quick to dismiss as "rebellious, arrogant juniors". I generally see two kind of seniors. The first group is senior in terms of experience and hard work. The second group got there only through obligation, working for years without growing a lot. Unfortunately, I see most management puts a hard cap on minimum experience before being a senior, so the former group and the latter group become indistinguishable. Other problems include Peter principle, where because someone got promoted to senior, he is now attributed as a good leader, despite having no experience leading as a junior before. Skills that are at best orthogonal are attributed to seniority, despite the fact many junior and medior people may be better at teaching, leading and mentoring others than their seniors. Nothing in the track guarantees a senior ever has to practice or show their excellence in these skills, either. Furthermore, most people aren't doing interesting things. They get a revolutionizing experience at work maybe once a month at best, if not far longer. Couple that with an echo chamber and suddenly, they believe it is normal to take 3 to 10 years to become an expert on fairly trivial domain knowledge. We're not talking about top-of-the-line C++ programmers, ML experts, people driving innovation, veteran software architects or whatever. We're talking your average CRUD web programmer who did some backend, maybe some frontend. We're talking people who believe one can only be senior being able to deploy an application from scratch into a new environment, thinking this takes at minimum 3 years to learn when in reality, you could pick up a guide how to do this today. The only real thing you'll miss out are office politics and navigating in a group setting. The former is so volatile and context-dependent, you might as well learn it on the fly or wait until 15 years have passed by and pretty much any possible situation has come up. The latter is severely overstated in difficulty and most people will pick this up in no time, unless the team is dysfunctional to begin with.