A lot of prod support can't be done remotely, for practical (need access to this physical environment) or security reasons.

In which case you need 24/7 shifts on site. If you can fix a problem remotely from your home then someone can do it in Sydney.

24/7 on-site is costly and counterproductive when issues are rare but high impact.

Someone in another country providing remote support doesn't work for a whole range of industries, particularly where security clearance is in play.

Even then, feels like.its easier and better for everyone if if instead of everyone needing multi-continental teams, you have one team, and if they get woken up and stupid o'clock to fix something, they get extra holiday or pay or something.

I know I like it like that. And I get that not everyone does! But IME, the out-of-hours rota is usually voluntary, so you can choose.