Does Intel or anyone still sell 32-bit x86 chips for non-embedded use? A quick Google was inconclusive, although it seems that while Intel sells low-power x86 chips under the "Pentium Silver" brand, they all seem to be 64-bit now. So eventually more and more old x86 boxes will be decommissioned, and 32-bit x86 will be dead as a desktop platform, no?
Which might mean people who want to run old proprietary 32-bit games/software are going to be annoyed, but that's not necessarily the distro/OS's problem; it could be argued that the user should install a 32-bit translation/emulation layer to run that stuff, ala DOSBox.
I believe the last x86-compatible chips without 64-bit support were launched around 2006 or so (Intel Core; Core 2 had 64-bit support), a couple of years after Opteron initially came out.
It's not really clear how long the Linux kernel itself will continue supporting such CPUs. The architecture certainly isn't something anyone really cares about (e.g. Meltdown wasn't patched for several months after it went public and 64-bit x86 got fixed).
Yup, I bought a brand new 32-bit Intel Atom tablet from Toshiba in 2014, gave it away but the person I gave it to is still using it. It has 32-bit UEFI, which is also loads of fun. I once installed Debian on it, but I couldn't get touchscreen to work, so went back to Windows 8.
Absolutely not... but hear me out. NetBSD plans on supporting 32-bit x86 until "long after 2038 (http://www.netbsd.org/about/)." Legacy hardware matters for many reasons. Outside of the fact that I still love my Lenovo x60s and use it as a distraction-free writing machine, much of the world still depends upon 32-bit architecture. We can't be replacing computers for all 8 billion people on Earth every 10-20 years. Hell, think about all the government bureaucrats still running MS DOS! :-)
There’s a crossover point though where the effort to support it is larger than the supply of newer hardware coming through. With the last x86 deaktop chips coming out in ~2006, I would bet there are very few viable use cases left. That’s 6 3-year cycles past.
I have seen many Windows 98 machines in the last ten years. I saw one just last week connected to a giant robot in a factory. So, if you are looking for use-cases for 32-bit, there's the fact that some giant machinery relies on computers that will never be updated.
Last I heard, even the last BlockBuster in the US is still using old PC's to run their DOS software. They harvest parts from old computers sold on e-bay. So, if you have any old computers laying around, they might be worth something these days.
You wouldn't really want to mess with the OS in cases like that, though. If you did, a lot of the OS-included drivers would probably not work due to removal or bit-rot, or 3rd-party drivers might not work with a much newer OS. The only reason you might want to upgrade is if the machine is Internet-connected, in which case you're probably just going to need a whole new box (if you need the old software, you'd probably resort to a VM), otherwise the new OS will run too slow (especially with things like new crypto/security). Or you can keep the old box but put it behind nginx or whatever.
Point of sale or industrial control computers are kind of just an offshoot of "embedded"; not something you need (or want) to run a browser or a modern GUI[0] on. You stick it in a cabinet or a kiosk and hopefully you don't have to think about it again.
I have a number of old computers lying around the house in closets, some 32-bit only. Linux not running on them anymore is actually pretty annoying since, as I said, that used to be one of its oldest mantras.
Outside of the enterprise crowd, Linux's next biggest audience are the tinkerers and hobbyists with too much free time and ancient hardware well past their Use By date. What a time it is that we can legitimately say it's better to run some version of Windows instead of Linux on them now.
The hobbyist Linux market generally tinkers with things like Raspberry Pis now, not ancient 32-bit x86 machines. (This is a natural consequence of the fact that sources for cheap hardware have changed a lot over the last twenty years.)
Which might mean people who want to run old proprietary 32-bit games/software are going to be annoyed, but that's not necessarily the distro/OS's problem; it could be argued that the user should install a 32-bit translation/emulation layer to run that stuff, ala DOSBox.