Would you use a circa 2001 ver of linux or macos?
I'm assuming you are talking about "PCs" as we normally thing of them, not special-purpose boxes, embedded systems, etc.
The answer is yes, if either
1) I had to, because my applications wouldn't run on the newer versions (think PPC-only binaries that I don't have the source for - okay, that's mid-2000s-era, but still).
or
2) it got the job done without any negative downsides and the cost to upgrade (license fees, new hardware, training, etc.) was too high. Think isolated (no Internet) systems OR the mythical (?) 2001 version of Linux or MacOS that was still vendor-supported and which had a supported security package available.
Heck, if Windows 2000 was still supported and it ran the software I needed to run (modern security software, modern web browsers with modern plug-ins, etc.) I would recommend it over XP to anyone with a sub-512MB computer.
Ditto Windows NT for computers in the 16-128MB range, provided I plugged all the security holes (disable LMHash, etc.) and my users were okay with a user interface that is as alien as Windows 8 is from Windows 2000/xp/7.