Where ARM has succeeded is in new markets (phones and tablets) that both rely on low-power operation and are relatively immune to legacy code or chip architecture issues. As far as I'm aware, Intel's never been successful in those spaces and even took the strategic step of dumping its ARM (Xscale) operation.
My point being, if Intel's secure in established markets and uncompetitive in newer markets, that's not a technological disruption in the classic Christenson sense. It's merely the consequence of earlier strategic decisions to not go after newer low-power application markets. Where would Intel be, for example, if in the early days they had dumped the microprocessor business to focus on their core business of memory chips?
edit: typo