Here’s my guess as to Apple's reasoning: They like to dominate suppliers, but TSMC is in such high demand that they’re on equal footing now. Going into bed with Intel gives them the chance to set strict terms again.
But it’s likely not a one-dimensional decision. Supply chain diversification, China / Taiwan, Intel having established US fabs, on and on. Seems like a wise decision in every way.
It's not clear if it's going to get better either. It could get worse in terms of supply.