They do though. A few years back we had a patch room next to our office and in one corner was this really ancient tower case. We took the side off once and it was something like a pentium DX4. Then someone suggested turning it off to see what happened. Before anybody could object one brave soul pulled it's kettle lead out. Later that day, a bloke wandered up to ask what had happened to his database. Apparently it was something to do with reporting for a national tax system. It had been running 24x7 for the last 11 years. It all recovered fine and it's probably still going.
Edit: I mean a 486 DX4 of course. Actually can't remember, might have been something else, but it was very old and very dusty.
EDITED: 10 Feb 18:17 by WILLIAMA