Very good question - I believe both the CPUs and GPUs used in the latest non-retina MacBook Pros use less power than their predecessors.
You'll have to wait til the proper in-depth reviews come out for these machines, but I'd wager that they have a longer battery life than their predecessors and that Apple probably just isn't marketing them as such as they don't want people seeing this as something these machines have over the Retina models.