As the probability of generators being kept running for that long is zero,
Methinks thou art missing a point. Power on time also includes when groun dpower is connected. Early on the 787 took a long time to boot up computers and system from power off. So as i understand it, Airlines were encouraged to connect groundpower and transfer before shutting down APU. Also, power up seemed to give a bundle of false alarms that needed to be reset- sorted out.
Thus it was ( is ? ) not unusual for a 787 to be powered on for several months, at least to the point of triggering the involved ' counter "
And redundant- fail safe systems should NOT have a common tie point which can trigger such an event.
