I can think of several possible reasons: - They store a lot so they get discounts - They use Infrequent Access, much cheaper than standard - Some users may c

I can think of several possible reasons: - They store a lot so they get discounts - They use Infrequent Access, much cheaper than standard - Some users may cost a lot less than their subscription fees helping to offset some of the costs? (not storing a lot of photos or whatever) - They might use Glacier which is a lot cheaper than both IA and standard And so on