Another option, of course, is software simulation. It is even worse with the really large machines, some of which require special power or cooling and are hard to keep running. However, it is hard to justify the expense and the cost of either the real things or the replicas. I have a replica Altair, a replica Elf, and a replica KIM-1. There have been a few replica retro computers of various degrees of fidelity and they are usually cheaper and smaller than the originals.

However, I got rid of my Data General hardware and I lost my old 1802 COSMAC Elf in some flooding. I do have my old original TRS-80, and an old serial terminal (see the video below). There are two things that keep me from expanding my collecting old computers: the cost and the space required to house them.