Look, I'm not an accountant, if there's one here to correct me on this I'm keen to hear it. I can understand that it may be useful to associate customer support costs to accounts in some ways. It obviously impacts unit economics. But none of that is what COGS is about (again, marketing is a major factor in unit economics and not traditionally considered in COGS).
COGS is about me as a customer buying a widget, receiving a widget, and the seller having to have made me a widget. That's an incomplete view of a business, but incomplete views can still be very useful. Understanding customer support cost for example must be done over some time horizon, i.e. what's the 6 month post-purchase support cost, which means we don't know the cost for 6 months. COGS is known much faster.
As for whether it should include storage, or any other particular piece of technology, for a SaaS business, I guess that probably depends on the business. The important bit for accounting is the direct cost of providing the service. If you're renting out GPUs by the hour then clearly a GPU hour is a direct cost. If you're just hosting a web app and not selling any particular slice of infrastructure then that's probably not a direct cost. Fixed size plan storage is probably somewhere in the middle, although cloud storage is clearly a direct cost.
Still, my point is really that businesses should only use subscription pricing when there's ongoing COGS, because that's what people intuitively associate with ongoing value most of the time.
