I suspect a lot of people don't share because of the few who believe they know everything.
Just because someone disagrees with you and cites science to support their side of the argument doesn't mean they know everything. This bit of slander has been tossed about before. It displeases me.
Also, the fact that certain scientific hypotheses do not support your currently-held beliefs does not mean they are more likely to be overturned in the future than hypotheses that agree with your beliefs. There are still people who believe the Earth is flat. I, for one, have not seen the curvature of the Earth myself; however, I have seen sufficient evidence of it thanks to astronomers, physicists, (i.e. scientists), and photos taken by satellites and astronauts to take it as a fact.
It is important to want to experience as many things first-hand as you can. But when someone claims to be an expert (and has sufficient and verifiable credentials for that claim) and they present evidence that they arrived at via the scientific method in an area where I am unable to personally test the evidence under similar circumstances, I tend to give such evidence credence. It just so happens that the opinion us "know-it-alls" tend to put forward is supported by such evidence.
Science moves forward slowly, it is true. Hypotheses are constantly revised as new evidence comes in. If a hypothesis withstands many tests without needing to be revised, it becomes a theory -- like gravity and evolution. These were once hypotheses, just like the "audio component X make(s) no difference" is a hypothesis. Until proven otherwise by contradictory evidence gained under controlled circumstances -- any evidence presented anecdotally, as yours has been presented, is of no use -- the hypothesis stands as valid.
