AWS + Azure have both gone down with major outages indivudually more over the last 10 years than any of the servers in companies I worked with in the 10 years before that.
And in comparable periods, not a single server failed or disk failed or whatever.
So I get SOME companies need hot standby servers, almost no company, no SaaS, no startup, actually does.
Because if it's that mission critical, then they would have already had to move off the cloud due to how frequently AWs/Azure/etc. have gone down over the last 10 years, often for 1/2 day or so,