In the sense of self-benefit, yes, it's rational.

>The difference between $100k a year and $60k a year is enormous.

Principles shouldn't depend on that though. Else "Yeah, I'd help kill kids and kittens for $1m" would also be an acceptable answer. $1m is also enormous compared to $100k.

Decent people have made much bigger sacrifices that living with $60K a year for doing the right thing...

Principles don't depend on that, but house prices do and if you know the house market in Germany then you'd get it.

I doubt anybody who is not a programmer making over 60K is homeless in Germany...