This is related to the fact that AMD is moving its chip design team to IBM headquarters, right?
Hardly. The AMD-Intel decision came a lot later than the Apple decision to move to HyperTransport must have come.
I think it's related to the fact that HyperTransport is a very good solution that has won very widespread support, and the fact that Apple need to strive to use PC technology wherever they can in order to keep costs down.