Let me clarify my points...
The WDW Motorcoach System (buses) is dynamic. More buses can be used during peak times, and fewer during non-peak times of day. Each bus can share the same stations and still follow a different route based on need, and this route can change throughout the day.
This is a daily occurrence at WDW monorails are taken offline after the morning rush and more are added in the evening as needed.
Although the number of trains on the system can be increased or decreased based on demand, for safety reasons, the entire beam-way must be stopped whenever a switch-track is engaged to add or remove trains.
My main point in this statement was multiple bus routes can share the same small station, a monorail uses a fixed beam meaning only one route can be followed. Just look at the footprint needed at TTC for just three beam-ways, compared to the footprint of the bus stations at Magic Kingdom that can service over 20+ different routes as needed throughout the day.
An example modified routing is the All Star Resorts. They can use three separate direct buses, one from each hotel, during the peak morning and evening demand hours, but share a single multi-stop route during the non-peak afternoon hours.
If a bus breaks down, other buses can be re-routed around the stalled bus to continue service. If a monorail breaks down, the entire beam-way must be shut down until the down train is removed from the rail.
On routes with multiple stops (for example Disney's Caribbean Beach Resort has 8 internal stops) once a bus is full it can proceed to its destination, and another bus can pick up where the last one left off (i.e. Bus A goes to station 1, 2, 3, then proceeds to Magic Kingdom, Bus B starts at station 4 and continues the route around Caribbean Beach.)
Monorails are quite capable of doing this also its just not as common, the monorails don't usually fill up at the first stop.
Aside from the Guest Services factors involved, for steady traffic flow reasons a monorail cannot simply just skip a stop along the way without backing up all the other trains on the same beam-way.
With three transfers and one additional stop, during peak travel dates the entire trip could well take a couple of hours factoring in wait times for each train and stop. Meaning to make that 5 PM dinner the family would need to leave Magic Kingdom before 2 PM. (Got to think of walk time too.) Currently this same family could board a bus at Magic Kingdom and proceed directly to Animal Kingdom, arriving for dinner in about 30 to 40 minutes.
This is very true, if a monorail expansion is ever done it would need to be well thought out to avoid situations like this. Ideally you would have one monorail route servicing all four parks and other transportation radiating from those hubs.
Again this cannot be done without multiple stops or multiple transfers. Just like for air flights, feedback from our Guests shows they want fast, direct non-stop routes to their destination. This would simply not possible on a fixed rail system with the many entertainment choices at Walt Disney World today. Also on your next visit, note the number of Guest using direct Park to Park transportation compared to Park to Resort routes. A fixed high capacity system simply is not need for the majority of the day.
Another factor not mentioned is when building a new monorail route much of Walt Disney World Resort sits on wetlands and protected conservation areas. Building a fixed beam system would required the beam to be routed around these areas and adding extra supporting and foundations for the pylons, driving up costs. It would be a lot less expensive to add roadways (and bridges over the protected areas.)
This is a common myth years of planning and studies have been done to decide what can and should be built where throughout WDW. Disney calls this the master land use plan, these plans take into account all future expansion, I have copies of some of these myself and I can say for a fact they do account for monorail expansion on "suitable to build" land.
True, studies have been made to find "suitable land" for possible beam-way routes, but to date they have yet to be utilized for reasons stated above. Foundation pylons have even been built into Epcot during it original construction for a proposed monorail expansion that can no longer be utilized due to changes in land use over the years. The Swan and Dolphin and the other Disney owned Resorts in the Epcot Resort Area were not part of the future expansion plans in 1980 when Epcot was being built. An Industrial Park was originally planned for this site.
The Master Land Use Plan has changed dynamically in the Resorts 37 year history and is still in a constant state of change. The master land use plans have called for a variety of different resorts, an airport, a mall and an industrial park that were never built. Also new parks such as Disney's Animal Kingdom and Disney's Hollywood Studios were not added to the master plan until a few years prior to their construction. The original Master Land Use Plan called for only 1 Theme Park to ever be built.
I think you will notice that very few roads have ever been rerouted through WDW everything for the most part has been a result of years of planning and only minor adjustments have been made.
Few Guest roadways have been completely moved, but several have been re-routed or completely redesigned. The interchange of World Drive and 192 has been dramatically changed
several times over the years. Also many parts of Buena Vista Drive has been altered over the years, as has Epcot Center Drive and World Drive. Some backstage roads have been moved or completely removed since 1971.
Again while an expanded monorail system would be nice, current guest traffic patterns and expectations, return on investment, and the uncertainty of future expansion makes it very unlikely.