The Share Everything Plans are insanely priced regardless of how much or how little data you buy on either AT&T or Verizon. $80/mo for a paltry 500 Meg of data for one smart phone on the account is just unconscionable. But of course these companies are looking for massive overage charges to pad their profit margins. What the consumer needs, wants, or cares to pay is totally irrelevant. So the simple answer as to "why" they don't offer what the customer wants is they make MORE profit by offering insanely expensive plans instead of more reasonable ones.