A vertically integrated manufacturer does
not necessarily mean their costs will be dramatically lower than the competition.
For example, Apple doesn't do any manufacture themselves, and yet they have costs so much lower than the competition that they are able to define entire new markets in the time it takes for their competition to develop cost-competitive supplies.
This has happened three times now, firstly with the original iPods (Apple pre-signed huge contracts for those tiny hard drives, proved the market, and when competitors wanted in they had to wait for new sources to come online), the iPod touch (Apple pre-ordered a huge proportion of the worlds flash memory supply) and finally, most recently with the iPad.
Ever wonder why it's taken a year for anyone to build a 9"/10" iPad competitor? It's because no one can get capacitative touch screen in sufficient quantities. Even Samsung (which owns the factory!) had to make do with 7" screens.
Now, finally new factories are beginning to come online, which means that competitors can release their products. The problem for them is that Apple locked in much lower prices (because of their bigger purchasing power), which makes it hard to compete on price. This applies to Samsung as much as to anyone - they can't afford to drop Apple as a customer, but the capital costs of building a new factory means it costs them more to supply themselves (selling in smaller volume) than it does to supply Apple.