I'm not sure I would call Bose snake oil, but the audiophile space certainly is full of it. On the one hand, you've got overpriced equipment that's not very good value but works, and on the other you've got literal scams like gold plated fiber optics and "audiophile-grade" network switches that are literally incapable of changing the quality of your audio because the signals are digital and have error correction, so it will either work or it won't. Placebo effect + choice-supportive bias are enough to get these things positive reviews though.