I cannot say that I agree with your reasoning. I think people stay offsite for a multitude of reasons, and while money may be a consideration, I doubt that it is the only consideration. People who choose to stay onsite also stay for a variety of reasons, and spending money like a drunken sailor may not b all that factors into the decision.
We stay onsite. I hate to drive. My husband is a professional driver who is on the road, in heavy traffic, hauling heavy equipment for the better part of the year. Vacation without renting a car, without driving is a priority when we go to Disney, and for us, it factors higher than accommodations costs. Others want or need more space, other families like their privacy. We value our money and work pretty darn hard for it, so when we plan a vacation, we start with what we are looking for in the vacation, and what our budget is. Makes no difference to me how Disney hides the components of a package in the final cost, I know what the package is, what I get for it, what OOP costs I will incur,and finally, if it is worth it to me.
I do not for one minute believe that what we see on that calendar is what the tiers will look like. I think it is a work in progress and when we see the final result, the offsiters will notice the cost increases the most, especially if they travel during th peak and holiday seasons. But the resorts already have the tiers in place, so this is just an extension. Annual pass holders will probably have more choices and price levels in place, and will either feel they can pick and choose what works, like a cafeteria style health plan, or find they hate it because they cannot justify the cost of the plan they like.
I have always thought that Disney was trying to find a way to offer an all inclusive vacation, but has fallen short because it is simply way to big to do so. I think this is one more step that Disney is taking to try to encourage guests to stay onsite, spend all their vacation dollar on the premises, and avoid taking those pesky day trips to the area attractions.