The bit about the car is silly, no comparison what so ever.
Why are people so utterly, tediously literal on the Internet?
Let's assume that what you've said is correct and, for some reason cars are outside the world of not buying the cheapest you can find. Use your imagination.
Do you have the cheapest jeans it's possible to buy?
Do you have the cheapest shoes it's possible to buy?
Do you have the cheapest carpet it's possible to buy?
Do you take your car to the cheapest garage available?
Do you use the cheapest tyres it's possible to buy?
Do you use the cheapest plumber available?
Do you buy the cheapest TV it's possible to buy?
Do you use the cheapest window cleaning equipment available (IKEA sell a squeegee for 95p)?
Do you buy the cheapest beer it's possible to buy?
Do you buy the cheapest food it's possible to buy?
Do you use the cheapest builder available?
Do you go to the cheapest restaurant in your area?
Etc, etc. Repeat a thousand times for all the things you purchase.
Hopefully at least one of those might just strike you as not "silly". In which case, think if there ever might be a time that you didn't just buy on price.
See, there's the point I was (pretty obviously) making. Well done. Customers are the same. They. Do. Not. Buy. Solely. On. Price. Nobody does.
Vin