"the biggest limitation we have in achieving true connectivity"
Is not actually battery life - it is security at the hardware level.
Battery life (or lack of) is a nuisance, to be sure, but everywhere you can hope to get a connection, you generally have access to a wall socket or a USB charger. If you go out of range of either, there's a good chance you won't have connectivity either.
What we really need is secure-by-design IoT. Another thing would be IoT that is actually useful and not just for hipsters, but that can wait until security is baked in from the start.