I guess you have never run a business. All it takes is one competitor to lower their prices in order to gain market share. The companies that don’t pass the savings on to their customers will find their sales dropping as they try to pocket their diminishing profits. Do you not compare prices when you shop?
I understand the need to be competitive. What I disagree with is your claim that if business taxes go down then that will mean that their prices go down by the same amount. That makes zero sense at all. If I am a business and my costs go down but I can still sell as much of my goods as I did before then I'm in hog heaven. My bottom line just went up. That's the nature of the system. I'm not going to adjust my prices until I have to. And if my competitors are in the same boat as me, reaping the same windfall that I am, then neither will they.
Businesses in the same industry may or may not pay the same tax rate. It depends on too many variables. You don't see businesses paying lower rates automatically dropping prices to offset their lower tax liability. And nothing in the Cain plan will change that from what I can see. Business taxes go down. Profits go up. They may use the money to expand, pay down debt, buy back stock, hire more workers, any number of things - many of them positive. But if my taxes double under Cain's plan then the idea that my costs will halve to offset it is flat, freakin' ridiculous. Cain's plan is a net tax increase for most people.