In fact, Apple has dominated the portable music player for a long time.
They also dominate the laptops market, making the biggest seller models of all the world. They make them in Aluminum(extremely expensive to make for small productions) and the big quantity they sell make extremely hard for others to compete.
They dominate the smartphones also. Other manufacturers have more market share but divided in lots of models, and several manufacturers.
The Ipads had been selling fro hundreds of millions per year. There is no sophisticated product in the world that have been sold at those massive numbers in the entire history of mankind.
This is something that Steve Jobs understood very well. The current CEO was the boss of manufacturing for a long time, so he knows it.
But if they continue raising prices, they will lose the mass production.