To add another perspective, I purchased a Maruti car in India about 4 years ago. On paper every variant from the lowest to the top has an 'optional' version with airbags.
In practice, the waiting period for any variant with safety features other than the top speced would be "over 6 months, no gaurentees". ie: as a customer, I was forced to buy the top end variant -- with alloy wheels, chrome trim and all sorts of other crap which I did not care about because I wanted the safety features.
I think that maruti is using safety features as a way to upsell customers who care about safety. The difference isn't a "marginal cost". For some models, the difference is 30% the cost of the car.
In practice, the waiting period for any variant with safety features other than the top speced would be "over 6 months, no gaurentees". ie: as a customer, I was forced to buy the top end variant -- with alloy wheels, chrome trim and all sorts of other crap which I did not care about because I wanted the safety features.
I think that maruti is using safety features as a way to upsell customers who care about safety. The difference isn't a "marginal cost". For some models, the difference is 30% the cost of the car.