Maybe lets not try to pretend that it is just about the costs shall we? I bet MBAs will cower at the suggestion to put up a paywall from the beginning. Afterall, bait-and-switch is their bread-and-butter.
Subscriptions weren't the norm when we actually paid for something and got the full product. The cost to run things didn't suddenly become a factor just now.
Only thing that changed: greed of businesses, execs, shareholders.