If you want to boycott every corporation that is trying to increase profits, you will lead a highly ascetic life.

That said, what you are saying isn't entirely untrue, and in fact is considered conventional wisdom by many. If everyone was a lot more price sensitive and more willing to forego discretionary spending, then yes, profit margins and prices would probably be lower. When boomers talk about millennials and their avo toast, this is what they are talking about.