Indeed. I still keep around a couple of old computers, because they have PCI slots (parallel, not PCIe), unlike any newer computer that I have, and I still use some PCI cards for certain purposes.
However, those computers are not so old as to have 32-bit CPUs, they are only about 10 years old, but that was because I was careful at that time to select MBs that still had PCI slots, in order to be able to retire all older computers.
The only peripherals that truly don't work in more modern boards would be AMR/ACR/CNR? ISA and plain PCI being reasonably easy to acquire expansion boxes (might be a problem for EISA though, I guess...)
Whether that motivates debian support is another question.