Everyone is talking about the cost per mile of monorail, but no one has said anything about the cost/mile of the roads at DW. If you have any increase in bus and car use, you need bigger roads and existing ones need refurbishment. There is already a massive congestion problem in many areas, adding buses does not help. Buses are a temporary fix that become less effective of a solution as time progresses.
I asked myself how much does it cost to build or refurbish a road. Take a look at the generic Florida DOT CPM estimation for different road construction projects. (link below) Looking at the examples presented, these type projects are not cheap. I would argue that the price for mass transit are with in reason when compared to cost of more roads which may or may not ease transportation issues.
Also someone threw out the $85-100 mil / mile cost for the Sao Paulo monorail, that price includes purchasing land right of ways, a cost that Disney would not have to bear.
ftp://ftp.dot.state.fl.us/LTS/CO/Estimates/CPM/summary.pdf