Discovery has taken some hate for the robot drones deployed in abundance. Personally, I don't mind them. It would make sense that Star Fleet wouldn't want to waste highly trained astronauts' time on welding and bolt torquing.
Still, I get the point that we've never seen anything like that in any ST before. The closest - assuming Data doesn't count - has been TNG and it's successors use of probes. So, while nothing we've seen before that I'm aware of strictly rules out drones having been there all along, sweeping floors off camera and whatnot, it does stretch credulity. For example, why wouldn't Away Teams send drone down first in cases like "Arsenal of Freedom?"
At the same time, way back in 1960-odd, Gene Roddenberry was a dude on a budget. Published notes suggest he was looking at what the future might be (most notably, communicators), do drudge-work robots seem unlikely? At the same time, he was trying to sell a studio on a weekly sci-fi movie whilst his competition was offerings like Mission: Impossible and Bonanza. Might there have been a notepad somewhere with a line crossed thru the term "robot mechanics," followed by "too much $$$?"
Roddenberry is quoted as having wistfully marveled at the kind of TOS S1 he could have offered with TMP's budget. I suppose one of the reasons the Disc drones don't bug me is I can see that they'd have had role if The Great Bird Of The Galaxy had funding enough for them.