I have student loans, for which the monthly payment is as much as some people's car loan payment. Were it not for that, I could easily afford to finance an STI. Even WITH the student loan payments, I could afford to finance, but then I wouldn't be saving nearly as much as I'd like to.
It's all about priorities. How much is it worth to you to drive an STI? Me, I'd rather drive a slower WRX and pave my way to a nicer retirement, or maybe spend money on things in my life other than cars.