Yes it would, the entire point of the project is to make a subset low-bandwidth standard. Highly optimized from server all the way to device. By not encrypting it they can even use multicast and caching.
When you visit an internet.org site, your phone wont load 30 tracking js files from 30 different companies. It will load the text of the page.
For all practical purposes, all of the cost for providing internet services at scale is in the last mile. In other words, it would not cost internet.org anything significant to extend the service to cover the whole internet. It makes very little difference in cost whether they backhaul the traffic to their datacenter or their closest peering point.
If the requirement is to only provide a low bandidth service then it is trivial to restrict the bandwidth usage per end-user, even if it provides access to the whole internet.
I feel a bit that people complaining about this service are self-serving. People here are complaining about things that affect them (potential future internet directions) and because of these effects millions (maybe even a billion) should be denied a free service.
I feel very, very uncomfortable with that viewpoint.
Apps like UC Browser and Opera Mini have been doing it even before we had smartphones. I still use UC Browser here as 2G is really slow. So the bandwidth used will be miniscule.
It's definitely possible for Facebook. In fact they've almost done it. The fact that they won't go the extra step and still insist on calling it "Internet.org" makes me suspicious of their intentions.
Let them go ahead. Call it Facebook.org and cut out the sanctimonious tone of pretending that it's charity.