Imagine unironically saying that someone potentially just a few years from 30 "is still a child." They... didn't? A developer who has a typical graduate academ

Imagine unironically saying that someone potentially just a few years from 30 "is still a child." They... didn't? A developer who has a typical graduate academic career, went straight into the software industry, and then had 5 jobs for less than 9 months each is probably in their mid-20s. In terms of technical skills and professional maturity anyone like that probably is still almost a child in terms of their career and the series of very short tenures definitely makes that more likely. Our time on Earth is limited, and five years is a non-trivial percentage of our working life. That's true. But as you point out yourself it's still only a relatively small part of our likely working life unless we luck out and reach FIRE status with a big exit or something. You can pick up some useful skills and develop an effective professional mindset in five years. But you'll do the same again in the next five and then again in the five after that.