A lot of those companies have such antique stuff there - it's usually way more robust than current ones. And very often, the software for such machines runs on DOS as it is way more stable then Windows... so you need stuff that is being supported by DOS
It's interesting. I've worked for manufacturing companies here in Canada for years now. Currently at a plastics manufacturing plant, but regardless of the industry you always see a lot of very, very dated computer hardware.
The reasoning is simple: If you just need your computer to do some simple task - be it print labels, update a database with production statistics or what have you, your circa 1990 PC will do the job just as well as a modern one. A new PC doesn't gain you anything whatsoever.
So, if the old hardware works, why replace it an incur the new hardware + software(significant, there) costs for no apparent reason? And those old machines run very well, and very reliably, in a rough & tumble manufacturing environment where they may be dropped, hit with forklifts, etc.
It's not just computers, either. At the print shop I used to work at, we had modern high end multi-million dollar web offset presses running side by side with ancient (originally hand powered, now motorized) presses from the 50's and 60's.
Nowhere is the dramatic loss of quality and sturdiness in
everything as the years go by as apparent as it is in a manufacturing shop.