But it only works sometimes
A glimpse is often more compelling than a certainty. For a minute or two, the drum solo on Monk's Dream is totally and completely alive. It even makes the neighbor's dog turn his head and stare at the speakers.
If all recorded music sounded this good all the time, it would lose its magic for me. I certainly wouldn't spend hours trying to get my stereo just right (one more time).
Word of mouth comes from intermittent delight. Things that work all the time are harder to talk about.
Random reinforcement drives people to focus their attention and effort, because it's worth sifting through many to find the one that's worth it.
Sure, there are places where six sigma reliability is essential (like pacemakers). But in most markets, your audience is likely to talk about your flashes of brilliance.
Sometimes, we're so focused on being consistent that we also lower the bar on amazing. After all, the thinking goes, if we can't be amazing all the time, better to reset the expectation to merely good. Which robs us of the ability to (sometimes) be amazing.
But amazing is what spreads.
In markets where some people expend unreasonable energy, we get uneven results, and those results are things we seek out, again and again.