I surprised it wasn't discussed here yet, perhaps I missed it. Transportpass+, Disney's next new offering. With an additional upcharge, you can skip the lines and hit the transport of your choice. Exclusive access to resort deluxe transport services. They've already tested the concept with the park hopping busses. It's a given that the guest foots the bill one way or another. The question is, will transportation be the last equal rights amenity on property. With the magic band system, anything is possible. There could be one premium service with the MinnieVans being the precursor, or perhaps tiered transport levels, that match your resort level.
Monorail towers may not last forever, but neither will skyliner towers, nor roads. All require regular maintenance. Someone will decide if repair is cheaper than replacement. I can see the Epcot spur being replaced with alternate transport means. I think the main line, will be kept alive if even at a reduced service.