Not all 3 have to respond all the time. It's a rotating schedule for having the overnight phone and the weekend phone (during weekend nights the SLA is relaxed to 1 hour).
And keep in mind, 20 minute response doesn't mean you fix the problem in 20 minutes, it means you respond in 20 minutes to the callout.
I think you're victim of an easy-going startup culture.
I’ve been oncall for escalations for like 15 years. That’s miserable enough, IMO frontline guys need fixed schedules and rotation if the volume is high.
I definitely cast my perspective on this and apologize if I came on too strong,
Sorry to say, you're right and he has Stockholm syndrome. It's a very aggressive schedule, must be missing holidays half of the time to keep the phone.
And keep in mind, 20 minute response doesn't mean you fix the problem in 20 minutes, it means you respond in 20 minutes to the callout.
I think you're victim of an easy-going startup culture.