But I didn't pay $20k to keep my current car from now on, so if it breaks down without the possibility of repair I still can buy some other used car and save money.
Now, safety features are important, but from what I have seen, modern cars are too soft - hitting another car at 40-50km/h can completely destroy your car, but when I hit some other car at around 40km/h, my car could be straightened out (though it needed a new headlamp, radiator and bonnet). Though the soft modern cars most likely are safer at very high speeds. But driving even a 2005 car (not very new obviously) on a gravel road leaves it full of dents (I guess driving it a few times on that road will cause it to start using less fuel).
Also, my current car does not have software in it (really, the car was made in 1982 and all controls are mechanical), so it is easier to repair (that and everything is easier to access - I do not need to remove a wheel to replace a lightbulb). So this may be worth to me the higher cost of fuel (then again, LPG is not that expensive compared to gasoline).
But we were talking about the fuel efficiency and how more efficient car saves money for everyone. Just like having your own solar power - while the power may be free from now on, I may have to pay enough money for the panels, installation etc to keep using grid power for 20 years. And the solar power will need periodic battery replacements, so the power is not completely free after installing.