Brown mushrooms used to be the cheap ones, as they were common. Someone discovered the edible white variety in their mushroom cave, and started growing them. Because they were so clean looking, they gained instant popularity, and were the "gourmet" mushroom. Everyone else jumped on board for the money, and the white button mushroom became the standard. Now the portabellas, and cremini mushrooms are more expensive, and thought to be superior. They might have a little more flavor than their white cousins, but not much. I'd be that if you closed your eyes, and had someone give you a sample of both, you'd be hard pressed to tell the difference, either in flavor or texture.
We place value on things, or rather, the producer places value on the things they produce. They will always try to maximize their profits, no matter that they price so many things out of the reach of ordinary folks. There are always enough privileged people to support their pricing practices.
The only recourse we have to pricing is the boycott. Very few people boycott anything. We have credit cards.
We can get it now, go into ridiculous debt, and pay the piper later, or so we think.
We are a ridiculous society anymore, IMHO.
Don't even get me started on medical costs.
Seeeeeeya; Chief Longwind of the North