Probably. Or something like the TPL5110 might actually suffice, purpose-built timer for power gating at 35nA, but only goes up to 2hr at max.
Nice, didn't know this one! This combined with a PIC10 without watchdog timer might also be an interesting combination to do more complex things. Or perhaps simply a TPL5110 with a ultra-low-power flip-flop (does it even exist?) used as a divider to get to 4 hours.