I've been following this thread for a while and I thought I'd add my two cents
The monorails were mainly stemming from Walt. Walt wanted the monorails as the transportation of the future, but now as technology has surpassed monorails with self-driving, low-emission cars only a few years away. The monorails, no matter how much I love them, are kind of a lost cause in my eyes. I feel like the only thing keeping them going is the cost that it would take to dismantle the entire system, including remodeling the Contemporary to fill the empty space.
On the money topic, face it, Disney is a company. The high-ups who would be making this decision would see the lost money in building this system and not want to do it. For them, the buses work fine. Add to the fact that self-driving cars aren't that far away, Disney may be implementing a new self-driving transportation system soon, which would drastically reduce costs, a newly constructed monorail system would be a huge waist of profits that could be used for something that would earn more money. Also. even if the operating costs are cheaper, it would be years and years and years before the become even, and by then, who knows what type of technology we'd have.
In all reality, and no matter how much I try and convince myself otherwise, Disney is a company focused on making money. The people who would be making this decision are focused on that aspect. Yes, we'd all be happy with a resort wide monorail, but the high-ups see it as the bus system works for these people, they'll still give us money even if we keep it that way. Also, they don't see profit in the new system, nobody would go to Disney just because they had the new monorails. Also, even though people might make reservations at other resorts, you still got to eat, and you'll still be paying Disney for food. Disney wants the people in with the cash, and doesn't really care what else happens. A perfect example is ticket prices. Disney will raise them because people will still come. Some people might not be happy, but they'll still fill up and get more money. MDE had high costs, but they'll be able to use that for years, and the amount of increased revenue they can get from that is very high.
I would love a resort-wide monorail system more than many, but it's Disney's decision. They see minimal profit gain and an extremely high cost. I hate to say it, but Disney's a company, and their #1 concern is gaining profit.