Laser cutter - probably fiddly to set up, but would be quite simple once you got going. (For hobbyist quantities, that is)
The issue I see there is cutting the paper in the right place and attaching the film. And if there would be a feasible way to have the process of 120 somewhat semi-automated instead of one roll at a time by hand.
If you can see a laser from the side, it is being scattered. If you can see it, be sure to put your goggles on!
Even if it worked, such as by using a far IR laser, the melted support may be a problem.
Making a male female gear couples or laser are fantasy. Best way is to use printing press house expertise. Rotogravure printing press houses print their subject on everykind of thick paper or plastic. These papers or plastics layups as hundreds of sheets at the end of the press machine. They have to cut and folded at too many applications at binding houses.
An expert binder get ordered with a computer output cutting pattern. Every binder have a man who prepares cutting patterns with folding thin sheets of steel and nail one end of these folded steel on to wooden board and other end sharp and free.
When you put this board on to papers or plastics and press from the top , folded steel cuts the thick several hundreds of papers like an butter.
And these guys are busy and get many orders per day. And they are cheap.
May be best way is to cut 1 meter long polyester bases for 35mm film and lay a 100 meters long film as 100*1 meter lay up and get cut at binder house for sprockets. And after all coat these sheets. No dark is needed , you can clean the cut pieces by hand .
We use them to cut polyester and polycarbonate.
When you aim to things you can not afford , its fantasy. Do you know the cost of cutting four gear from steel , align at a base and rotate them when you are feeding the film with many other gear train. Its hell of money. Its like you wanted to buy a mini , it is expensive and you want to build SAME !!! factory to own a mini.
People were mentioning backing paper numbers on 120. Surely 220 only has leader/footer paper at the ends - so why not for 120v2 as well, and using a camera without a red-window of course. This is all a bit of an academic exercise though, for general use at least.
The reality is that punching perforations in the film and finding suitable backing paper are fairly trivial things when compared with making and coating the emulsion.
I think the trick is to use people's skills. One person on his or her own might struggle to do it all but a few people with different skills might do it.
e.g. I am interested in emulsion making but will probably never do it myself. However, I'm sure that I could make a coating machine and a simple jig to cut perforations if someone else wants to coat the film.
EDIT: That wasn't an offer to do it, just a hypothetical scenario!