Many things

[der Mouse]

> PostScript is infinitely more friendly to Classic Computers than PDF.

Hm, not in my experience.

> A PostScript document can be easily handled by someone who has no
> computing technology younger than 1985, that's almost 20 y old, not
> just 10.  No graphical operating system required (how the heck is one
> supposed to run Adobe Acrobat on a vintage command-line OS with a
> VT100 terminal??),

You don't need Acrobat, no matter what a bunch of webpages may claim.
GhostScript groks PDFs just fine.

Indeed, ghostscript comes with a script that eats PDF and produces PS.

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