The other answer could be lack of scale. These aren’t artisan goods that someone can easily try offering on a whim, these magnificently complicated machines are

The other answer could be lack of scale. These aren’t artisan goods that someone can easily try offering on a whim, these magnificently complicated machines are only affordable because of economies of scale/mass manufacturing. You can probably find someone to custom build what you want, but it’s not going to be anywhere near cost competitive with a standard model. Maybe you can get close by using stock parts from other cars. Or maybe this is a market opportunity, and you should set up a manufacturing line for stripped down jeep-like vehicles. Probably won’t be road legal, though, because they’re horrifically unsafe in a collision compared to modern cars.