That's a very naive take on the economic realities. Supply is very often determined by input costs. If it costs more to provide a product or service, supply drops driving up prices, which in turn can lead to a drop in demand. Depending on market elasticity, one common way the market gets out of this negative feedback loop is by compromising on quality in order to hold down prices.

You can see this in the current economy as restaurants and packaged foods suppliers in some sectors reduce the size of portions.