Earlier quoted context omitted.
Look up the 4% rule and firecalc.com to learn how this 100x multiple is a lot less, more like 25x realistically. A lot of people are irrationally intolerant of risk. Try not to let fear dominate your intuition about investing.
That 4% is empirically derived from data covering the 20th century and is appropriate for earlyish retirement. There's two reasons to be more conservative: 1) We may be in a low-yield world for a long time. 2) Those studies were based on earlier retirement, not on people leaving the workforce in their 20s and 30s, the way that some very lucky HN readers may do.
It's a tricky one to work out, and 4% is (as you say) definitely not a number you can easily use for retiring in your 30s.