"Everything is governed by supply and demand and that never remains static."
That is very true. However, it is also true that any business that consistently sells its product at less than its total costs (including tax costs) won't be in business on a long term basis. Also, any business that doesn't provide its owners a competitive rate of return for their investment won't be able to attract capital in the future.
True, but if you can sell an item for $20, it really doesn't matter whether it cost $0.02 or $.25. Or $5.00.