Your assuming that most people eat a healthy diet everyday. Theres a lot of people who doesn't get every vitamin they need to function at peak levels. Taking a vitamin pill won't work as magic as it sounds like you expect, but i assure you most people can benefit from a daily multivitamin pill.
Whey protein compared to casein does yield better results directly after training, besides whey protein is cheaper than almost any other source of protein. People who claim that whey protein is useless or doesn't 'work' clearly has no knowledge about nutrition. If you eat perfect in every meal, every day, every time then no you could argue that whey protein is useless. But let's face it. Its alot more expensive to eat perfectly, and who has the time or effort to do it? Protein whey is a supplement to a already good diet, its nothing else. If you don't eat properly from a start, whey protein isn't the answer, but to those who eat well but still has troubles reaching protein macros or doesn't have the time for a meal filled with protein during busy times then whey protein is the answer.
Heres 1 minute of digging:
http://www.hussmanfitness.org/html/TFPostProtein.html http://www.sciencedaily.com/releases...0818132225.htm
About the creatine. Creatine doesn't directly affect your strength levels. Creatine mainly increases burst strength which isn't directly related. You can't really average it since its much different how some people respond to it. I don't feel much difference when taking creatine for example, but it does over a period increase my max output. However a friend of mine does over a 2 week loading period get significantly better output. Last source i've seen said that about 25% of all people is so called non-responders. Non-responders is just people with naturally higher occuring creatine levels, which means the extra supplement doesn't do much.
"no supplement will makeup for having a proper diet and healthy outlook.".
I would bet my right arm that there is a lot of supplements that you could benefit from, and everyone else. Sure with the perfect diet there wouldn't be many supplements that made sense, but as mentioned earlier. Eating a perfect 3-6 meals a day that exactly fits your macros and micros is pretty expensive and time consuming. I'm a poor and busy student, i can't afford it with either money or time. You need to understand what supplements are, not pretend that they're some overhyped magic shit, only people who doesn't understand supplement tend to belive that.