I wonder who initiated this - Apple or Samsung.
If Samsung, it's definitely a risky move to refuse to serve your biggest customer. It obviously leaves Apple with an enormous components problem - we've heard constant reports that LG and Sharp cant meet Apples quality expectations. Quality doesn't just appear from nowhere, though - the huge orders are building up Samsungs already-enormous experience in manufacturing LCDs, while rivals remain behind.
Apple should be investing directly in to companies like Sharp. It will allow them to buy the best tooling and hire the best people, and if managed correctly can bring their quality up to Samsungs level. The direct investment gives Apple the ability to sway higher-level management and ensure this this happens, as well as prevent them doing anything similar in the future. Not only that, it makes great financial sense, too - with some Apple-sized orders and the aforementioned better quality, these companies should thrive and give an ample return should Apple ever decide to divest. Its basically betting on yourself, so that increases the risk, but Apple would probably be fine with that; they expect to do well and don't need additional motivation.