Linux has a rule to "never break the userland". So if you maintain your own userland(libc/gui libs, etc..) even the latest kernel will run your old software.
> "The 32-bit Oracle 8i database will no longer run on modern Linux."
Yes it will.
> "I forget the exact errors, but the software is simply too old."
You're running into compatibility issues with newer libraries. Libraries do change in incompatible ways -- but the solution is simply to install the older library.
You absolutely can run 32-bit Oracle 8i on a modern kernel. The steps to do this in a nutshell (omitting a few details) are:
1) Grab a linux userland which 8i was built for (eg: RedHat7) and extract it somewhere. Use docker, create a chroot, whatever you like.
2) Enter the container/chroot and install 8i. It'll work fine, because you'll be linking the correct library versions and those libraries will still work even on a modern kernel due to the aforementioned kernel compatibility guarantees.
True, but users don't care why it breaks, only that it does, and most people consider "the distro" to be Linux.
So you probably CAN get old Oracle databases to run on the latest kernel, but all the supporting software would be a weird mishmash of old libraries, etc.
VMware is a different beast altogether. Maybe it'd remove the maintenance of a physical NT machine, but you'd still be maintaining the whole NT software system, and honestly that's most of the headache. Plus the overhead VMs have and all.
Containers run on your kernel and hardware natively, with a tiny bit of shims from the kernel side so it's a different root and possibly removing raw hardware access. Oracle 8i should run just as well as it would have 20 years ago, if you have all the userland libraries in order (hence putting an old distro in the container).
As long as Oracle isn't internet-facing (you can setup the container's networking however you wish, with whatever firewall rules you wish), it should be fairly safe. The modern kernel you run it on should be up to speed on the latest security patches too.