The monthly subscription was a way to cover hardware and software upkeep cost,(servers, content, fix bugs, CS)at the time before wow number for subscribers was expected to be a lot smaller so the free to play model was inconceivable, and unsustainable, Example is Everquest show more than 225,000 subscriptions on 1 November 1999,with an increase to more than 450,000 subscriptions by 25 September 2003, that's less than half a million.