At a small shop I ran our VCS on my workstation (because otherwise we had none) and at the end of a day I rebooted to do some maintenance on the machine, and it didn't come back online until around 1pm the next day. On the plus side we finally got a dedicated server.
That said, you still gotta touch systems.
If you get off the upgrade treadmill, you will find yourself one day facing a CVE issue that have no patches for the versions you use. And then not only do you have to do a security update, you have to fast-track a version upgrade that your code might not work with anymore.
Last time we had this, I got the team to agree to putting one upgrade of OS or libraries per month onto the task list. We even let the assignee choose what they were going to upgrade (a few had no preferences, and so we'd have them work on whatever was most overdue).
We put some caches in place at work recently, to improve perf and give us some protection against partial outages. Already we are seeing services that cannot handle the same workload they could three months ago.
To paraphrase Jim Highsmith: there are no answers here, and we waste enormous amounts of time looking for them. There are only tradeoffs, with their own sets of consequences to be managed.
The tradeoff I prefer is to drill it into people that shit happens. Something is going to be down, and the more things we have, the higher the likelihood that one of them will be down at any given moment. You can put all of your eggs in one basket and have one outage a year, in which everyone not involved in fixing the damned thing might as well go home, or you have a bunch of systems where I can do 80% of my duties if any one of them is offline.
Systems that are never seen to break (or at least stumble) tend to become siloed, insular. Being able to talk about the 'bigger issue' around an outage is often a time when teams finally communicate with each other (unless you have dysfunctional managers, in which case: run)
And if all else fails, there is always some set of tasks you want people to do but they never seem to have the time for. Having a captive audience isn't the worst thing that could happen to you.