This is wrong on so many levels.

No they don't.

I know plenty of people who have had to sit around for 8+ hours because the particular type of doctor is not available. The on call only really applies if you're bleeding out.

In my 20+ years of development and support, there has only been once that I was paged due to an actual catastrophic failure. Most are because shitty "SREs" wants monitoring on everything, even if its stuff that I have no control over.