This is *not* an announcement that IBM *is* providing the CPU silicon. This is a cross-licensing agreement announcement only.
Don't count your eggs before they are hatched. These same licenses, I would note, are utilized by AMD in their x86-64 chips, and could note a shift from Intel to AMD just as readily as a shift from Intel to IBM. Knowing Microsoft, they are playing these three off of each other to drive the price down.