I'm not sure that really proves your point. You've made about 2.8% annually over 13 years, not including your borrowing cost, agent fees, etc.
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.