I do wonder what the trends have been in number of cars parked vs attendance. It seems to me that increased proportion of on-site guests with transportation included might reduce the need for available parking - or at least has slowed growth over time.
At some point in the far future, few people will need parking because most will just have their self-driving car drop them off.
A pre-cast parking structure has a 50-year lifespan. Given that autonomous vehicles could preclude the need for a parking structure 30 years from now or sooner, I wonder if we'd ever see one?
Note that another nice thing about a surface lot is that the ground prep and water management prep are a good first step to building a hotel or other structure on it, so strategically it may be preferred to build another surface lot than a parking structure.
I'll additionally wonder whether we'll see Disney experiment with water-permeable parking lot options. Or I wonder if those just don't make sense for them due to ground permeability/saturation issues - that the water would be standing for too long so it's better to redirect to retention ponds to prevent standing surface water in the lots.