Intel could become complacent again;
K7 and K8 were excellent products but they were only as successful as they were because of Intel's mistakes, not because Intel became complacent. It was the strategic mistake of dumping P3 for Netburst *and* insisting on it for 6 years that allowed AMD to blossom with K7 and K8. If the world didn't take a turn towards mobile, which forced Intel to work P3 as a low power architecture, outside the netburst team influence, Intel would be in dire trouble once they saw they wouldn't be able to go past 4Ghz.
AMD wouldn't need Intel to become complacent again, AMD would need Intel to make another strategic mistake like Netburst. And even so, I doubt that AMD would be able to capitalize on it given the poor state of their balance sheet, that honor would go for Qualcomm, Mediatek, Samsung and others.