I might be wrong, but isn't the only mandate for improved mileage? The carmaker can make whatever choices it wants to achieve those goals. (I don't think even incandescent headlights are illegal).
I'm old enough to remember the oil embargo, when the US discovered just how dependent it was on unstable countries for its energy supplies. Gasoline prices were measured in cents before hand. Every President since has promised energy independence and no one ever beleived there was a chance of it ever happening. Now it seems that this goal may actually be in sight. You could argue whether or not this mandate should exist (rather than just making gasoline more expensive and let the market decide how to respond), but I think that this is what started it all.
Specifically about car lighting systems, the incandescent lightbulbs are surprisingly expensive. The author claims the cost to be around 1$, but I seem to be paying around $5-10 and even $20 for the main bulbs. At this point I haven't seen reasonable-priced compatible LED car bulb replacement, but I expect them to start showing up. soon. Similarly, the fancy house bulbs (say PAR style) began to have comparable pricing for incandescent and LED technology, so I stopped buying incandescents.
You could certainly make the same argument for pollution control equipment and for safety features built into cars, occasionally voluntarily by the auto makers, and almost always eventually mandated by governments. At least with lighter body panels and such, operation of the vehicle is not impaired. You can't say the same thing for pollution devices, starting with the initial, crude, exhaust gas recirculation and spark retardation systems in the early to mid 1970s, which caused very poor fuel economy, not to mention sluggish performance. It took years to get engines to perform properly again - I'd say, it took until the 1990s.
All of these increased the cost of cars. Does anyone think we should go back to the cars of 1966?
The auto makers are having to meet ever more stringent fuel economy requirements, which is why they cannot avoid these upgrades. If it were left up to me, I'd consider making it far more difficult to sell obnoxiously wasteful vehicles, with blunt and tall front ends, much like the Ford F-150 you mention, which so many automakers try to emulate. I'm not convinced that the EPA fuel economy ratings take into full consideration the appalling aerodynamics of these ugly behemoths. Changing fenders to aluminum hardly seems like the most cost-effective path to improvement.