*Crosses fingers, hoping that the futurist predictions regarding self driving cars eliminating the need for parking garages are true.*
Seriously though, it's a possiblity that self driving by 2035 could be practical, affordable, and ubiquitous.
If they built a garage in 2035 (give or take), that garage would need to be useful for how many years for it to "pay off"? If in almost twenty years, self driving is not yet 100% here but at 50-75%, how big would Universal want the garage to be? Would they even want to build one knowing it may only be useful for another 5-10 years?
I know this is planning very far out (not just 20 but 30 years) but that's the point. This is a business decision now... With the idea of "who knows where we'll be" in the future. If it was my money, I'd take the safe route with a parking lot, not garage.
(Please note, I'm speaking of full, self driving, not just driver assist.)