Computers don't exist in a vacuum - the environment is constantly changing.
Let me put a real-life example.
Say there's a new SSL vulnerability or zero-day discovered - you go and check to make sure all your servers and packages are patched. Or maybe there's no patch yet, and you need to run a mitigation.
You better go check all your logs, to make sure nobody got in already though. Hmm, maybe you should contact your NOC as well, just in case.
Load just increased - you better spin up some new servers. Whilst AWS might like you to believe this is all one-button and it works with no human intervention - it probably isn't.
Oh, drat, one of the uptream endpoints you rely on just broke their API. You better whip up a patch. Then you need to test it, and make sure your CI server passes all the tests for it. Oh, and then hire some testers.
The point is - things are more complex in the real world, particularly running at any kind of scale.
I see this all the time with people that know zilch about technology, but it really disappoints me when I even see my fellow technologists underestimate the amount of engineering effort it takes to get something simple like a server up and running reliably.