of course suppiments work – anyone that says different is dreaming. i.e you 'suppliment' your intake of protein, you are metabolising more of it so it'll do more of it's job of rebuilding broken down muscle fibres if it's needed. If you are doing anything other than sitting around on your ass on the internet it stands to reason that you won't need to 'suppliment' a healthy balanced diet, however if you are doing anything that breaks down parts of the body you need to 'suppliment' a normal balanced diet, be it with food (not as efficient and probably more expensive) or through what you are calling suppliments.
And the 'we suvived thousands of years without it' argument, errrrrm how long did folk live back in the day ay? Maybe not as long as they would of done if they had a couple of protein shakes a week an a multivit!