LO2 reserve in any hospital should've been enough for weeks per refill.

And hospital with on-site O2 generation should've never had any issue. Any industrial scale O2 production machinery would've had many times the capacity reserve.

But they didn't. Double digit of hospital O2 generators were out of service, and LO2 tanks were never filled to full because hospitals were saving on LO2 service.

Some hospitals with central O2 systems from either tanks, or generators simply had them disabled for unfathomable reasons, had them broken down years ago without any attempt at repair, or simply never ever used them, so they don't know how to operate them.