Bitcoin might be the inspiration but certainly not the reason why altcoins are appearing.

You already mentioned that humans are fueled by their greed to create money out of thin air, and they can do that by creating yet another cryptocurrency to get people buying. They just got the idea from bitcoin, but their reasons on creating that coin is not bitcoin per se so there's a difference in there.

No matter how many times people campaign against obvious scamcoins, if there would be enough gullible people around to buy the hype, nothing would change in the scene.