If cars were built like houses, each one would be built outdoors, exposed, in the middle of a muddy field.
If cars were built like houses, each car would be slightly different than all others, and would be built under different laws, depending on where in the country the muddy field was located.
Each part of the car would be put together and installed by a different company, with different workers guided by different supervisors, on different semi-dependable schedules, if cars were built like houses.
Sometimes in the rush to finish the car, the battery or steering wheel wouldn't arrive in time, so we'd just "put it on the punchlist" and get to it later.
If cars were bought like houses, no part of the car would be tested by anyone except the buyer, who'd just make sure the paint looks nice and the seats feel good.
If cars were bought like houses, car shoppers would never drive the car before they bought it, and no one would ask about the mileage per gallon, since no manufacturer ever bothered to measure it.
Also, I forgot to mention that these cars would cost hundreds of thousands of dollars- the biggest thing you'll ever buy.
If you hate this story, then next time you shop for a home, look for home performance testing and quality control checklists.