The strangeness of Silicon Valley right now is that if you're lucky you can "retire" long before 40. I'm 31 and have through a bit of luck accrued a small 7-figure net worth. I don't plan on being a "rank and file" employee by 33, let alone 40.
The entire Financial Independence (FI) movement is all about doing this everywhere (not just the valley) and without luck aside from household income around $45,000/yr in the US.
Plus modern retirement isn’t necessarily “never work a job again.” It’s more a freedom to do what you want (income generating or not) without having to take a job simply to cover your cost of living and retirement savings.