A reasonable investment portfolio (in the US) will reliably generate enough inflation-adjusted growth on average that this will afford a modest lifestyle in mos

A reasonable investment portfolio (in the US) will reliably generate enough inflation-adjusted growth on average that this will afford a modest lifestyle in most parts of the US. $35-50k/year (today's dollars) without much risk, which is a fairly average wage. It is only unrealistic if you live in an expensive city with a lavish lifestyle. Anecdotally and ironically, many tech people that do this end up making a loads of money after they "retire". They don't sit on a beach and do nothing. The ability to be highly selective about what they work on, and to defer any compensation, often leads them to invest all their time on software projects they are passionate about, which not infrequently ends up throwing off a large amount of incidental income even though that wasn't the objective per se. I like the term "recreationally employed" to describe this lifestyle. I know many engineers who ended here and some of them make more money "retired" than they did work the 9-to-5 grind at a big company.