But the folders and box cameras all have a window.
And I *LIKE* my Mother's Brownie Hawkeye.
I do agree that sheet film is a lot easier. And even at the width of 120 I have a bunch of 2.35x3.25 holders.
Plus i have a stash (No! It's not a hoard!) of glass window panes. So I too would probably try very little roll film.
When I think about the possibility of home manufacturer I invariably think small scale, dozens instead of thousands. The investment to make occasional new backing paper seems trivial compared to a perforating machine. Unless you can get or fabricate the perfing machine vey inexpensively.
For a small manufacturing operation, say 5K rolls of film, a usable perfing machine begins to make sense. And you could sell the film packed in a wrapper for the user to spool. Eschewing the cassettes.
I have some oddball FSU film in my freezer which is packed this way. It's just a strip of perforated 35mm film. The user had to load it in a cassette.
Some of the old Contax cameras had a refillable cassette.