Sorry Tongxinshe, but the situation is (thankfully) much more complicated than that, and there is consequently much more needed to understand this than your narrow view on pricing.
Examples are ecosystem value and gravity, price elasticity differences between Apple and competitor products, branding etc.
If it were so simple, than Apple would have lowered its prices long ago. As it happens, the iPad is the best selling tablet on the planet and probably also the most expensive based purely on its functionality and performance.