I assume it's part of the pay. You can't be a firefighter or a cop and then complain that there's night shifts. I've had nearly 4 years of it at a payment gateway and IIRC only one time was there something that had to be solved that night. When it happened, it was sort of my fault anyway; a good deal of the problems are (should be?) within the control of the people being on-call. And I think companies like payment gateways and cloud services which need people active at all times are also far more tolerant of things like spending a week reviewing a PR and such, so the frequency of downtime is lower even if the impact is much higher.

Though I'd agree it's a staffing issue. 5 people in a cycle is fine. If you had a concert or something that week, just swap places with a colleague. When we reduced it to 2 people, it was not cool to spend half your time on-call.

There's also policies like don't release on Fridays, don't release on a vacation week. If there's a tool for it, it would be flagging these behaviors. Unfortunately, we can't really control when partners go down.