The general urbanist consensus is that parking structures are a good idea sometimes.

Basically, if you are trying to revitalize your downtown, a government owned parking garage can function as a replacement for parking outside existing shops. This way, a previously walkable downtown can drastically reduce its existing parking while still accommodating a largely motorist clientele.

On the other hand, they are a less good idea in already dense and valuable urban centers. Urban parking lots are already expensive. Urban parking garages are enormously expensive. And they are counterproductive to the aim of getting people out of their cars and getting them to take transit into and around downtown. Especially in larger cities, the case for public parking garages is fairly difficult to make, since if an area is popular enough to justify a parking garage, the land for the parking garage could probably be put to better use in the form of a public park, housing, or businesses. And if a parking garage is truly needed, then a private developer could build one and turn a profit.

The problem is that probably the best place for parking garages in a city would be at a popular transit stop near the urban/suburban divide, to serve as a transition point between auto oriented and transit oriented commuters. But if you built a transit stop at the urban/suburban divide then hopefully that area will be experiencing infill quite quickly, and transit ridership will access the network via foot. Meanwhile, if you build a transit station far out... why build a parking structure, which is expensive, when you could build surface parking, which is cheap? And as a bonus, surface parking can be sold off easily to developers so they can build housing, whereas parking structures would require significant retrofitting to fit this need.