What do you think the market price would be if developers did not have to supply a minimum number of spaces?
That depends on a number of factors:
What type of soil/rock is the structure being built on?
Is there underground water?
Is the development next to the lake?
What are the site conditions and constraints?
How large is the development? (economies of scale)
How deep is the parking garage (cost increase expodentially per parking stall the deeper one must dig - i.e. is cost a lot more per parking stall at four levels underground than one)?
Other factors include fluctuating prices for materials (steel, concrete etc.) and labour.
Most developers los a significant amount of moeny providing parking - even when charging $20k per space, those costs are recouped by increasing all the unit costs in the building.
I know of many condos years after they were completed that still have unsold parking spaces that sit empty due to city enforced parking regulations that are out of step with market demand.