Things that would increase cost to these passenger cars:
Lights in the domes
Fully detailed interiors
Specific domes for each road name
So if those were all "fixed" and the prices were then increased, people would then gripe about the price even more than they already do. I would invite you guys to compare the prices of the 21" cars to the aluminum cars.
To me, these are beautiful cars that are a great starting point for customization.