Airbags, active suspension systems, ABS, backup cameras, etc all increase the cost of cars. Though I dont know how much of that is tied to increasing price of used cars - that seems to have more to do with Cash for Clunkers taking a huge amount of used cars out of the used car market, while it put a bunch of people in new cars, it also skewed the pricing for used cars higher - it took an entire generation of used cars out of the market - which continues to effect pricing today.
Electronic stability control is not active suspension, those are very different things. ESC isn't really even part of the suspension setup at all, it modulates the brakes in response to steering angle input & a yaw sensor.
Airbags, active suspension systems, ABS, backup cameras, etc all increase the cost of cars. Though I dont know how much of that is tied to increasing price of used cars - that seems to have more to do with Cash for Clunkers taking a huge amount of used cars out of the used car market, while it put a bunch of people in new cars, it also skewed the pricing for used cars higher - it took an entire generation of used cars out of the market - which continues to effect pricing today.