Apple should have turned to TSMC well before now. Even though the result of this trial is not satisfactory, I don't think Apple will then stop there and turn back to Samsung as the demand for their product is huge. I just wonder which company, besides Samsung and TSMC, now is large enough fulfill Apple's big appetite.
I am actually surprised that Apple hasn't tried this with a foundry before now. For products as popular and in-demand as the iPod/iPad/iPhone, I would have expected them to move a viable second source already on key components. Perhaps they have but it was not as public as the situation is now vis a vis competition with Samsung, so they managed to keep it under wraps.