The idea of reading actual books or technical articles is not a very good revenue stream. You're spenting too much TIME reading and not buying anything. AT&T isn't getting any of your cash from download charges.
You aren't reading any flashy magazine content from monthly subscription paywalls with ads for still more flashy subscription content.
Or rehashed works with added animation widgets also from subscription portals.
I don't know what the iPad was intended for but it 's not a reader.