So by your math I made a mistake buying used... Lets see.
I paid $14,800 for a car with a BB value of $18,800.
I put about $100.00 into front brake pads and rotors turned.
I detailed the car myself for about $100.00 in materials.
So for 15,000 I have a car that originally sold for $26,000. It is 3 years old and will touch 40,000 miles this month. I can drive this car trouble free for another 60,000 miles and I will have paid $15,000 + misc repairs.
This car would have cost me the same money + $11,000 or so if I bought it new and it would be in similar condition that it is now.
Why would I buy it new?