Preinstalled Windows is only cheaper than separate copies of Windows because MS decides to price it lower - precisely to perpetuate its use as a lock-in mechanism. So your price argument is a circular one.
Tires and cars is partly a decent analogy because there are similar bundling deals used with new cars, but there are a couple of big differences - there isn't a convicted monopolist behemoth tire manufacturer dominating the market with a more expensive and arguably inferior product that's bundled with virtually all cars, and not only do most people not drive their car on the factory-fitted tires for the vehicle's entire life, but they'll be forced to change them early in the car's life.
In fact if I was buying a car, I'd love to have the option to choose some Kumho SPTs or maybe even Dunlop Z2s over the bargain-bin all-seasons or slippery eco-tires that most cars come with.