My take is that cryptic error messages have always been a cross between 'protecting company secrets' and 'never really admit to a mistake'. Sure, MS or Apple could just throw up a dialog that said "Sorry, we trashed the file you were working on, here are the last 1024 chars" but people would actually be more angry then, instead of just "Error 1234 occurred" (or at least they'd have to go look it up to be mad).
As developers, we also have to be used to a lot of completely unhelpful errors. Yeah, couldn't connect to the DB, sure... oh, but actually because my code ate all of memory, why didn't you say that in the first place?
I suspect it grew out of electrical engineering. Machines/parts could only return errors as integers, so you would expect people to open up the documents and read that error code 1021 meant that the unit had caught fire.
Software just kept the tradition of error codes, since that meant you could also sell that juicy documentation (localized into whatever language you wanted) to the user as well. I suspect it also a localization issue because OracleDB would never return the table/column in the error message, so as to be easier to translate.
As developers, we also have to be used to a lot of completely unhelpful errors. Yeah, couldn't connect to the DB, sure... oh, but actually because my code ate all of memory, why didn't you say that in the first place?