It's amazing that career lengths in this business are split into "first few years", "1-3+ years" and "5-7+ years", given that most people will have careers of 40 years or more.
Most people won't have a 40 year career in a high paying industry like software engineering in silicon valley. A huge amount of people in high paying positions don't stick it out for 40 years straight. People become burnt out, have kids, live off savings/their partner, or just pay off their mortgage and live an lower-stress life. Sometimes people die, get long term sick, retire early or retrain. Or they hit a glass c…
Maybe you won't find people in their 60s working in the startup scene, but that doesn't mean they just drop out of their career, which you seem to imply. Most just go to work in established companies. I work with plenty of people over 60.