National Periodicals (DC Comics' previous name) used to print several different comics in the 1940's more than a million each, on a monthly basis.. That was with 1940's technology. It was the same with several other comic book companies back then, each book was printed at a million copies, or more. I don't see printing a million copies a week to be a big problem.
Benny seems to have a lot of lead time built into his printing. He can probably handle a few print problems, if he has to. He can also farm the job out to another print shop, if necessary.
I don't know what the costs of bags and printing them are.
I don't see these as being big problems. The larger problems are getting enough advertiser slots filled at a good CPM (Cost Per Thousand) rate. If the company is profitable , it really doesn't matter what the costs are. Profit is good.
If the company isn't making a profit, it is bad.
