What it really matters is the revenue and the profit, no matter if they are sold units or increasing the number of subscriptions, after all it's a new business model for the gaming industry so we know very little about how the developers monetize their titles on subscription services. Afaik they get money by signing a deal with the subscription platform and they also get more money depending on other factors such as the number of installations, hours of gameplay, among other activities.
And again, Netfix, HBO and Prime Video are successful companies making money from releasing AAA movies on their platforms, besides AA or B rated movies, that's a fact.