What is email, actually
Email was created to serve as a "dumb pipe." In mobile network parlance, a "dumb pipe" is when a carrier exists to simply transfer bits to and from the user, without the ability to add services and applications or serve as a "smart" gatekeeper between what the user sees and doesn't see.
Carriers resist becoming "dumb pipes" because there's no money in it. A pipe is a faceless commodity, valued only by reliability and speed. In such a market, margins sink to zero or below zero, and it becomes a horrible business to be in.
"Dumb pipes" are exactly what users want. They want the carriers to provide fast, reliable, cheap mobile data connectivity. Then, they want to get their apps, services and social products from, you know, the Internet.