If you think, as the question implies, that Apple wasn't told about emergent IBM chip technologies, I'd say you're crazy.
Anyway, Apple won't grow that much with just a faster CPU. By getting Intel's support, and breaking down walls that isolate them from the Windoze world, they can more easily pull over switchers.
with their current momentum, they need to stoke the boiler, make the big bets. Their ability to roll out new technology and navigate the transition seamlessly is a huge competitive advantage.
yup... solving hard technical problems elegantly... sounds like Apple!