Well there'd be a transition phase and an honoring of existing contracts to some extent but the way to do it would be to slow roll the release of customer ISA u

Well there'd be a transition phase and an honoring of existing contracts to some extent but the way to do it would be to slow roll the release of customer ISA updates or stop providing ISA updates altogether, e.g. anything past ARMv9.4-A would be in-house only. After 4-5 years competition would be struggling.