No, that's not the implication. Probably impractical for a 30 year old with three kids, should be doable for most thrifty people in their 60s, barring a catastrophic illness or if they are very generous in helping others. Also very much depends on the lifestyle. I know people who live in my neighborhood with 4 kids who spend $100K per year, and people with four kids who spend a million a year. (The difference is private school - $260K a year for 4 kids, $4K two bedroom 5th floor walk up vs $25K a month grand 4 bedroom apt, vacations, take-out & restaurants vs cooking at home, two nannies vs none, etc...)
@Santayana, interest income can also be cut unless you are buying treasuries in nominal terms, and in real terms in the case of treasuries. If you are long short-term treasuries, you run the risk that interest rates decline and so will your interest income. If you are long long term treasuries, and then 2020-2022 inflation comes around, that's surely is a cut in interest income, albeit real and not nominal.
I am not against buying insurance (in this case having a cash cushion), my point is you cannot hedge against everything, so where do you draw the line?