There are legitimate reasons to pull in someone after hours, but it really has to be catastrophic. I'd 100% want to be called in if I deployed something knocking out 911 service for a whole state and I was the only one with the knowledge to actually fix it in a timely manner. However, most problems are not like that and are either able to be delayed until an actual business day or can be solved by someone else.
Let's be real, we're talking about line of business apps and ecommerce stores making $5,000/day total revenue. "Critical infrastructure" has an entirely different failure model.
