note that all underground parking garages in Toronto are now required to be "bathtubbed" regardless of location in the city. Normally this is only required in areas of extremely high water tables (i.e., waterfront fill land), but the city has not been building stormwater infrastructure to handle the pumping from all these new underground garages throughout the city, so now requires it everywhere to "fix" the issue.
In other words, this parking garage will likely cost just as much as an underground garage basically anywhere else, which is still expensive.
For sure, though I think the difference here is scale. For instance, our standard operating protocol in today's cost environment is that the premium associated with bathtubbing a typical 750sm tower-and-podium site is about $3M over no tub (on sites with otherwise clean geo/hydro-g contexts), so scaling up even just that sort of premium to a 1,000-spot garage that's sitting on fill is immense.