Some bar napkin math:
$150k (savings) + $40k (living expenses) = $190k post tax.
Assuming 30% goes to taxes (making liberal use of a 401k), that would be $272k salary. @ 35% it would be $292k.
I think the reason everyone is annoyed/down voting is the assumption that every developer in the bay area is pulling top end salaries like that. The reality is the median dev salary is a lot closer to $140k/yr. It's also quite difficult to live on $40k/yr for most people in the bay area ($3.3k/mo). It's definitely possible but compromises will be made (e.g. no children, live with partner/roommates, have no expensive hobbies, no travel, etc).
Assuming everyone is as fortunate as you, and is willing to make the same compromises as you can come off as condescending, as if everyone is is screwing up and they just need to do this simple easy thing you are doing. It's akin to "why don't you poor people just earn more money??"
With that said, congrats on kicking ass at the savings game, and I hope you enjoy your early retirement :)