Regardless of whether anyone is an idiot, I don't believe people have the time to be knowledgeable about the vast majority of things they buy. People underestimate what luxury it is to go buy absolutely anything from a store while remaining fairly confident that you're not making a huge mistake. Modern society depends on this efficiency to some extent.

Then there's the problem that just a few people who don't care could ruin it for everyone else (for example the environment).