Okay, let's look at the facts:
"a great way to decrease pollution" You haven't posted any facts to support this.
"decrease long term costs for transportation" You haven't posted any facts for this.
"increase revenues to connected resorts and shopping areas" Once again, you haven't given any facts on this.
"increase guest satisfaction" Hello, facts, where are you?
Your overall statement has some good numbers, but your closing statement is all speculation and opinion. There are no hard numbers to support these statements. And these numbers would be very difficult to get, because some of them are numbers that only Disney would have.
The following is a quote from Inverno (Tyler) from the infamous "Monorail Expansion" thread in 2002.
Okay... I'll try my best to estimate a few costs... (Mind you, these are not solid numbers, but merely my best estimation based on factual numbers that I have seen, and my knowledge of Disney Transport & Monorails)
Monorail Trains -- $17m per train. I'm going to say we'd need 24 additional trains. That's $408 million right there, JUST for the trains alone. Never mind guideway, or stations. Guideway averages about $5m per mile. (I say average, because straightaways are cheaper... but curves/grades and special situations cost more). I'd guess we'd need approx 30 miles worth of guideway. About $150 million right there. Plus about $50 million for guideway within the resorts. (More on that later)
Now... We'd need to build a new train storage and maintenance facility. Those can get very expensive. Lots of switches, and lots of equipment. $10 million at least. Now, we have to build stations at the resorts, as well as a "Grand Central" type convergance point for all transfers. Now, keep in mind, I haven't even gotten into how on earth we'd fit a monorail into some of these resorts. Theming is a big element. And so is location. And they don't come cheap, either. We'll just say $200 million for all of the resort stations.
So far... thats $818 million dollars. And we haven't covered misc expenses, or "over budget"... because you know it'd run over budget. And, I didn't include replacement of our old trains. That would add an additional $204 million, which would make the grand total over ONE BILLION DOLLARS.
Okay, so yeah, maybe money does have something to do with it. But I can assure you... this system as I have described... would be the most efficient monorail system that they could build. However, it would take 2-3x as long to get to destinations, and require transfers. (two transfers to get to the MK... unless we rebuilt that system, which would cost another $50+ million.
By the way... Disney could buy about 65 busses for the price of one monorail. (not including guideway). Those 65 busses would have the flexibility to go anywhere at any time... bypassing other busses. Going off route to take someone someplace special. And most importantly... if one bus breaks down, they can quickly replace it. If one monorail breaks down, the entire system goes down.