For software engineer resume rot is definitely a thing. Everything has a 5 year timer on it even thr stuff that doesn’t out right die. C# has been around for like 20 years something like that but try to only know about the ecosystem from more than 5 year ago and you’re gonna have a bad time.

I can’t speak on network or sysadmin stuff, but I do know from a coworker friend that they get paid way less are are considered more expendable, so you’re probably right that it’s work that doesn’t change much. Still I’m surprised to hear you say that you have a lot of downtime or maybe I have only worked at trashfires

As someone in the field. I assure you, you do not work just a few hours and then go home. Software development take infinite time and any well run shop will definitely notice if you work a half day by your output vs others. IT is even worse since problems are basically constant.

I guess you can work at badly run shops, but enjoy being laid off and then failing to get a job eventually from having a stale resume.