For educational purposes, I tried to run some of the latest high-profile viruses in a virtual machine and on Windows XP some of them still somehow worked, on Windows 7 almost everything worked, and on Windows 98 none of them (At least without KernelEx, which is disabled by default). Giving errors, approximately as I gave above.
The thing is that the target audience of Windows 98 is too small for the authors of malicious programs to have to be so perverted. They compile not with the newest, but with what still works in XP\Vista\7. Absolutely not caring about compatibility with 9x. They are guided not by the recommendations of Microsoft and EOL, but by the popularity and prevalence of the OS on the Internet. This was already five years ago, and maybe earlier (I did not check). Now it's probably still "worse", the spread of Windows 10 \ 11 makes you adapt more to them. What's the point of writing an expensive virus for two and a half cripples?
I just tried it on purpose, downloaded the last three virus files detected in 24 hours. None of them worked under Windows 98:
In Windows XP NINJA earned. And Clip1.exe refused to work at all on a 32-bit system 😀
vbs.exe wanted .NET Framework v4.0.30319 or higher (which I naturally don't have in XP, and even more so in 9x).
This is what the overall picture looks like. Modern viruses are written for x64 platforms, for the new .NET Framework, the rest want at least Windows XP (or higher).
For example, you can give several names of modern viruses that have made a lot of noise in the computer world over the past five years, I will try to test them on my own (In a virtual machine, of course, with the network off). And none of them will work under Windows 98 with a guarantee of almost 100%.
And to protect against old viruses, as I wrote above, you can install ClamWin with fresh databases, in which all known viruses of the past are already included (And modern ones are still included). Although these old viruses are already very difficult to find on the Internet (If you don’t search purposefully).