Come on, that's just silly and it's a deliberate strawman. The options are not just between a $500 camera and a brand new car. The whole point is that the type of person who eschews the myriad of much cheaper camera options is also the type of person least likely to own a car that doesn't already have a built-in backup camera.
the tens of thousands is for all the other similar value propositions they'd want in a car.