One of the problems, touched on by the article, is that parts stop being made. I wonder if you could build a working IBM PC clone today.
Military systems are sometimes upgraded without changes in functionality simply because the old parts aren't made any longer.
Yes you can! There's the NuXT[1] which is a full system, or you could use PC-104 designs to build something approximating an IBM PC-type system from a later generation.
That would probably be one of your best hopes for building a computer today that's likely to have long-lived (in the sense of availability) parts even though it's probably not a drop-in 8088 replacement at the hardware level.
https://maker.pro/pic/projects/z80-computer-project-part-1-t...