I thought it sort of depended on how big the pots were.

Studios have one or two wee pots, factories have huge ones.
I consider Studio glass to be something individually made by the artist themselves, but there are pieces I know of, in Wroclaw Museum, which could well be described as early Studio glass, being individually made, one-offs, but made within a factory setting, using the factory facilities.
Then there was the short lived Dartington Studio, attached to the factory, and there are also a load of Caithness "Studio" style limited edition pieces.
Factory is more where you have a designer (who often doesn't make the glass) and craftsmen churing out lots of pieces to the design.
I think a lot of studios
are pretty much turning into factories, nowadays. They need the income from little, standard, cheaper, more mass-produced items.