I don't know if they would have to squeeze the battery. I've got a 15" MBP and when i am working on battery, i am on integrated pretty much all the time. Actually I use my dedicated GPU almost isolated on BC Windows, where i'm playing bf3. It's not like a dedicated GPU would destroy the 7 hours battery life while surfing ; its running on integrated anyway then.
I wouldn't debate you, except that I have to use gfxCardStatus to keep on integrated because programs that don't need it (skype, mostly) activate the dedicated card. And unfortunately, Apple has to cater to the average user. The average user doesn't have gfxCS, nor can they be bothered to care. All they will do is complain when their computer doesn't get the battery life they want (just look at every other new thread.) Apple has to cater to everyone now, even the people not technically inclined. That's why I don't think they will do it.
Plus, they need to continue to differentiate between the 13,15, and 17.