People like to have a product just work, and don't want to work to make it work. Even if it's a simple matter of running the tap, screwing in a refill cylinder, and off you go, that seems to be too much effort for all but the most dedicated greenies. And when it comes to food products, maybe refilling feels too hippie, and like you're not getting truly fresh, new food? Does size matter? Could it be that people don't get the mathematics? Perhaps people are still going on the bigger is better, more is more school of consumerism, and when they see a smaller version of something they've bought for years, it's in their minds not worth paying the same price? Or even if it's cheaper, the product somehow seems insufficient and not of equal quality because it's not as big, and the small bit of DIY required makes the product less substantial, less "genuine"?