[lucysmom]

But if 10 companies sell a widget and all of a sudden, their cost goes down 20%, one or more of those companies will try to undercut the others until the price point is driven down by the amount roughly equal to the drop in costs.

And companies will be able to lower their prices because...?

[xcamel]

Because people who have no concept of the difference between markup and margin think they can dictate tax policy.