The higher the demand for any good or service, the more the supplier can charge.For example, gas is a necessity, so the supplier can exploit our need for it by making us pay whatever they want.... we are their Mercy.If has was not a necessity and we do without it, it would be a lot cheaper.
Business succeed when they give the consumer what they want or need.The better the product/greater the need, the more of a desired object it is and the business can take liberty at raising the price.
Products that are not as desirable, for whatever reason, don't have such a "pull" for price hikes.
Hope this helpled.