Earlier quoted context omitted.
If I recall right, Mr. M.M. defines retirement basically as financial independence, regardless of how you spend your time. Working because you want to is very different from working because you have to, so I'll buy it. And as far as I know, he and his wife earned their money in tech jobs. The math is believable: let's say your household makes $130,000 a year (which I haven't done), and lives on $30,000 a year (which…
To live off of $30k/year, you only need $750k saved, not $1MM (@ 4% annual withdrawal rate).
EDIT: Missed that this was for a fixed period of time - 30 years.
But... what happens if you live more than 30 years past your retirement? It would really suck to retire on $750,000 (or $1M) savings at 45, and live to be 100.