If every cloud service arguably overprices one essential part of delivery, bandwidth usage in this case, my instinct (no more, no less and no pretension to analysis) is that there's a design intent to ensure a difficult to price component of the service provision is paid for.

I'm merely speculating, but if you have a idea what is the possible difficult to price component, can anyone help with any suggestions?

Edit to suggest a similitude: my job is to help people understand the price of (print) advertising. This is often intractable. To a certain extent, a good deal of people involved just throw costs into commission rates and other factors that make understanding the price models difficult and sometimes completely opaque. Is it impossible to imagine that the cost of cloud bandwidth is nothing less innocent than "put our non itemized expenses here'?