A similar argument could be made for a whole host of subscription services (gyms, television, etc.) but I think they all keep the subscription model because the mental transaction cost of buying a small amount of the product creates a huge barrier to use. Mental transaction cost is the stress that the buying decision places on the buyer. Someone once said that the only two prices on the internet are free and infinity, so any incremental cost is stressful. Additionally the prices needed to sustain a per-unit sales model are so high that nobody wants to buy. A great recent example is ski resorts. Before the Epic and Ikon passes, day passes were expensive but not insane. With these passes, however, the ski companies have decided to dramatically increase the daily cost and lower the subscription cost to maximize revenue.
A gym isnt something where I want to consume the service of 10+ companies in a day. More traditional television subscriptions (even streaming) are still bundle based sets of channels from multiple providers.
