Renting gives you greater mobility too, which can be used to maximize income.
if you spent the same in rent, you would have lived in a 2-3 bedroom for 20 years, moving every time you changed jobs
20yrs is a LOT of time to be living in the same place you can afford downpayment when you are 20yr old. and a LOT of time to work/study on the same area
On the other hand, the S&P 500 returned 8.25% annually between 1993-2006. Say you put 10% down ($8500) and spend $800/year total on taxes, repairs, etc. (probably low). If you'd invested in an index fund, you'd have made $42,000.