How much Power do speakers really use ???????

I have a debate going with a friend . How much power do the average speakers really use (not maggies etc) . He scoffs at high end amps that are rated at 100 -150 watts solid state and tubes as underpowered. I say that most of the time you are using less than 5 watts or so. And what do massvie power supplies and capacitors etc really do technically. What do you guys think? Thank You