Infrastructure projects suck. At our place, implementing a simple Enterprise Resource Planning system is costing Millions, and we only have 10,000 staff worldwide.
The costs involved are insane, for a project like MM+. Rather than going over budget, I really feel like they under estimated, and came up against alot of unaccounted costs. Not to mention contractor software development, as there is no way that was in house.
The USA pays on average over $100k a year to one single project manager.
Not sure anyone on the internetz will have guest spending info available, Disney seem to keep all that stuff very close to it's chest. All I've ever found is Chinese Whispers, no published documents.