Internal combustion engines might not be the best example. They've seen REALLY impressive gains in the last couple of decades. =) Today you can buy relatively

Internal combustion engines might not be the best example. They've seen REALLY impressive gains in the last couple of decades. =) Today you can buy relatively affordable cars with 2.0 liter engines pushing 300 or more horsepower and doing so with greater fuel efficiency than cars with much more modest output from ten or twenty years ago. (admittedly some of the gains in efficiency have been obscured by increases in vehicle weight)