For Americans this leads to “If my car gets twice the gas mileage, then I can drive twice as often!”
And fluorescent bulbs… just leave the lights on! Actually you kinda have to, as bulb life is diminished by on/off cycling that any cost savings is lost by bulb replacement.
Unless the government did it first and too the extreme, it would backfire. For example, a couple years ago, Los Angeles was thinking of restricting lawn watering due to a drought. Queue film of then-Mayor Antonio Villaraigosa’s lawn sprinklers on in the hot afternoon sun. Also, many people pointed out that if there was so little water, why were new houses being built in the desert? Talk of water rationing stopped.
Unpopular with you and me, maybe, but politicians know better than to bite the hand that feeds them.