> Even if you assume that all your expenses are linearly multiplied
Problem is, they aren't. Income taxes are regressive, so your percentage income to taxes goes up as you get paid more. Everything else should scale linearly.
> (hint: Amazon costs the same no matter where you live)
I spend maybe 3% of my annual salary on Amazon and similar websites. It's a non-factor.
> If you were living on $40k/yr in Kansas City, you could move to SF and suddenly be saving $80k/yr.
Only if your expenses go up by the same scaling factor as your salary. As soon as they get out-of-whack even a bit in favor of expenses the math starts to break down. It also breaks down if you are saving a small-ish portion of your salary to begin with.
Problem is, they aren't. Income taxes are regressive, so your percentage income to taxes goes up as you get paid more. Everything else should scale linearly.
> (hint: Amazon costs the same no matter where you live)
I spend maybe 3% of my annual salary on Amazon and similar websites. It's a non-factor.
> If you were living on $40k/yr in Kansas City, you could move to SF and suddenly be saving $80k/yr.
Only if your expenses go up by the same scaling factor as your salary. As soon as they get out-of-whack even a bit in favor of expenses the math starts to break down. It also breaks down if you are saving a small-ish portion of your salary to begin with.