I assume you are aware of the "bit-bang" mode of the 232R?
I'd like to buy the engineer who came up with that idea a drink of his choice.
Nothing that people weren't doing with real serial ports (and parallel ports) long before USB was a thing (and before those ports disappeared from PCs)...
(in fact, "ponyprog" was an early PIC Microcontroller (and others) programmer heavily used by hobbyists back before arduinos were a gleam in anyone's eye, and it worked by bit-banging an rs232 port)