Dear #HistoricalSewing -verse, have you ever stumbled on late victorian / early 1900s instructions on how to sew knit fabric at home?
I don't think I have, and all of the references to knit garments I can think of are of things that one would buy ready made, and thus sewn in an industrial setting.
Which is not any kind of proof that people weren't sewing their own knit underwear at home, of course.
Like the lack of wires into Roman ruins doesn't mean that Romans used cell phones…