Basically, you’d need enough space to be able to slide an entire separate one-sided building in front of the parking deck - plus another 10’ (to avoid having to run fans 24/7 because the garage is “enclosed”). Given that parking decks are only built in places where land is expensive, and that decks have very unforgiving minimum geometries (the most efficient spiral deck is 120’ wide and 190’+ long to get both the ramps in and parking spaces along all the driveways) it’s really tough to hide the entire deck within anything less than a full-block site… which has its own deadening effect on the streetscape.
Yes, smaller-footprint decks do exist, but they’re less efficient at getting every available parking space per floor - and so they cost considerably more per parking space. That might be worth it in a place where people pay $$$ for parking, but not here.
The elevations shown really overstate the visual impact of this particular garage, which will be screened by other buildings on two sides. Only the Morgan side of the garage won’t be behind something else.