You must admit that $40k bonus after tax is a huge, atypical amount of money. It makes your effective yearly income to be about $156k.
It reminds me of the mrmoneymustache.com guy, saying "anyone can retire early! Just look at me, all I had to do was get $1M in stock from Cisco!"
No disrespect intended for you; I'm sure compared to some of your friends you lived frugally. The point I'm making is that to duplicate your living standard today, very few comparable developers would be able approach your level of savings.
Not sure what typical bonuses are these days, but I don't think that's out of line for a big tech company. Certainly stock grants can be much more than that, but it usually takes more than 18 months for them to amount to anything.
[1: I am an engineering manager at Google]
The whole point of the original statement was "I made $X and saved $Y, it's not that hard." But when you examine the X and the Y, they are not representative at all!
It has similar merit to a lottery winner saying, "why can't you win the lottery too? All I did was buy a lottery ticket."