The only on mobile thing may have been necessary for the business model.
Maybe "compared to web pages". But very skeptical it's a meaningful cost compared to production or subscription prices. Even going with a third party CDN you're probably not paying more than ¢1/GB of transfer. For 720P h.264 that's about about 2GB, or 2¢, per hour of content transferred. How many pennies per month do you need before it's a meaningful portion of the $7 subscription price?