IMHO early cheap PCs were machines like the Commodore 64, Apple IIe, and the like.
You could do business on those machines, with some limitations. We had a word processor on the Commodore 64 that through some black magic even managed to have a spellchecker. The big downside was that our 9 pin dot matrix printer couldn't print descenders so characters like g j and y were pushed up a couple of points.
I'm sure there are people on this board who can tell you about industrial equipment controlled via a dongle hanging off of the cartridge port on a C=64.
One of our early automated tools on the inkjet cartridge assembly line was controlled by a hp calculator that had an expansion slot. I think the app that opened and closed valves and actuators was written in BASIC. The workmanship of those things was at least as good as some modern PLCs.
These were home computers, not PC's. Basically glorified desk calculators, though the multimedia capabilities were impressive for the time and some office work could be done on them. The industrial control jobs you mention would be well within Arduino territory today.
And even those were not "cheap" at all in modern terms; the cheapest would cost around $500 or so in today's money.
You could do business on those machines, with some limitations. We had a word processor on the Commodore 64 that through some black magic even managed to have a spellchecker. The big downside was that our 9 pin dot matrix printer couldn't print descenders so characters like g j and y were pushed up a couple of points.
I'm sure there are people on this board who can tell you about industrial equipment controlled via a dongle hanging off of the cartridge port on a C=64.