Uh, if all you need is to write documents on an air-gapped machine, it seems like practically anything would do the job. Any Mac of any age whatsoever, a typewriter ...
But the barriers to file transfer get larger the farther back you go.
I have two old Macs that I use for writing: a 1985 Mac SE 2/40, and a PowerBook G4 1.67ghz.
The SE is indeed pretty thoroughly cut off from the world, but this also means that if you want to get your data off the drive, you have very limited options to do so. In my case it means using an SD card-based floppy emulator, writing to virtual floppy, loading the SD onto my modern Mac with a dongle because MBP2019, renaming the virtual floppy file so that Disk Utility will still recognize it, and then finally hoping I remembered to save the file as plain text because nothing is gonna read that shit other wise.
I have experimented with a Wifi232 dongle as well, but found that getting a vintage version of Z/XMODEM to talk to a modern one is all but impossible in 2020 and I failed at almost everything I tried.
So: enter the PowerBook. At 1.67ghz it's actually beefy enough that with TenFourFox you could technically get to some websites, but other than a handful of Mac abandonware sites and the old version of Reddit, almost nothing else will work thanks to JavaScript requirements. So distractions remain minimal and the alt-tab addiction is kept at bay.
BUT, it is still internet-capable enough to be able to connect to modern WPA2 wifi (mostly, I had some compatibility issues with my old ISP router that required working around with an old Airport Express), and that means I still have ways to more directly share the fruits of my labors. Email works just as well as any modern machine of course, USB is there (albeit slow 1.0 speeds), and some of the older sites I post my work on even still work in TenFourFox. More recently, thanks to Tigerbrew, I've got working git, so I can even backup my stuff to Github.
The PowerPC line makes a very nice "bridge" generation. Just modern enough to still by able to connect to the outside world, but old enough to be relatively free of distraction, or at least to keep the Twitter habit out of the way while I work.
My uncle was using a 25+ year old PC running DOS and WordPerfect up until he passed away last year. I think he enjoyed the distraction free environment.
Is there a word for such long-lived computers that aren't hobbies? "Retrocomputing" is people goofing around. A person who drives a 1995 Honda is probably not a "retromobility enthusiast". Maybe at some point in our future it won't seem weird to use a 25-year-old computer.
I still use an old Acer laptop from 2008 as my private laptop. It's more than enough for my needs, but apart from it being good enough for my needs, there's not really any particular reason for using that specific machine (apart from the keyboard being amazing). It simply works fine, and I see no reason to replace it.
I don't know why there would be any specific word for it. I just use it.
Nothing will ever beat the T430. Oh the keyboard, the trackpoint, the disabled trackpad...
Have one at work and doing everything I can to avoid the upgrade-bulldozer-team finding me.
Bought many refurbished in perfect state. I plan to hoard them till I die, one every ten year (worst case). Need to up my battery cell expertise level for that...
Heirlooms maybe.
Oh the glee of taking it /by the screen/, to not worry the thing's gonna break...
Do we need a word for it? I've got a 1996 Toyota van and a 2ish year old Dell XPS, both serve my needs well enough. Some new tools are appreciably better than older ones, others aren't; I generally prefer to not spend extra money/time for things in the second category.
The 25-year-old car still takes a driver's time and some fuel, and moves stuff around just like a brand new one would. There's no hope of using a 1995 computer for compiling a big C++ project from a fancy IDE, while video chatting over WiFi. Remember that a computer from 1995 would've seemed a bit old in 1997 too.
Not great for compiling a big c++ project, but then again that's pretty much the top end of "normal" demands (I haven't had to use c++ in over a decade for example & worked as a developer the entire time).
A top of the line 2008 desktop (especially if it had been occasionally upgraded but even if it hadn't) will still be faster than a low end laptop as described above (the kind you can buy for €200-300 at Lidl) & perfectly good for front end web dev (what I happen to be doing for a living currently).
It would upgradable be something like 3ghz core 2 quad, 8gb ram and reasonably fast (non-m2) SSD. I've certainly done web dev on less than that.
While 25-year-old car lacks many of new tech gadgets it still is likely to have most important conveniences (A/C etc). The most important difference is safety (while not death cages like cars from 50 years ago, 25-year-old cars are still light years behind current cars) and emissions. The latter means that soon those cars might be banned from cities (at least in Europe), which renders "moves stuff around just like a brand new one" invalid.
I would rather be identified by what I use the tool to accomplish, not by the particular (age) tool.
The risk/reward of car travel in 1996 was OK with me at the time... It's great that cities are considering banning vehicles over emissions - I bike, walk, bus, or take the electric car (recently bought a Leaf) when just moving myself. The van is for moving big stuff and/or longer rural trips; it's an example of a tool that still serves my purposes and is not something that I want to be identified by.
I think we could be there already if not for a few niggling details. The first iPad mini has just been vintaged by Apple, and my laptop won't be supported by Big Sur.
There's nothing technically wrong with the laptop either, it's got max RAM, as much as the CPU and logic board will support, the drive, battery and wireless card are all replaceable, you can take out the optical drive and replace it with either one that supports Blu-ray or replace add another SSD, no USB3 ports but it does have Thunderbolt, Gigabit Ethernet, IR for an Apple Remote and an SDXC slot. Apple's just up and decided they're done supporting this laptop from 2012. A few forum posts I saw indicate if you were to force Big Sur on, everything but the wireless card would work. The only major silicon difference between this computer and models that are still supported is the integrated graphics, but without working wireless it's a bit of a non-starter.
I could buy a couple of replacement parts and easily keep this thing going for another 5 years or longer, which I still can if I'm willing to give up on Mac OS X entirely. What I'm probably going to do is keep it going another year or two and replace it once the dust has settled a bit on ARM Macs and Apple has proved they're not going to take their Mac line down a ridiculous direction in the next few years, then maybe replace the operating system and find another use for the machine.
Unless you're pushing the bleeding edge of performance, machines like this are still plenty good, especially if your RAM floor is 16GB. It's not the fastest, another machine I use for work screams by comparison, but there's not really any good reason a 2012 machine couldn't still be ticking along in 2037 if you've parts to service it with. Serviceability is really the only limiting factor at this point. That said most Macs that came after mine lost a lot in serviceability, so that's the caveat.
The problem isn't so much maintenance or performance as interoperability. I used to enjoy old Macs (pre-OS X era models), but gave up on them when sharing data became a chore.
