Parking is either on street (and therefore a subsidy to the business) or in parking lots. Either parking minimums or street parking requires vast asphalt pads empty most of the time, because you have to account for peak capacity.
Why is the county requiring more parking than the market value? The developer has no incentive to under-build parking - nobody would rent in the building if there wasn't enough parking available.
Edit - Des Moines has 19.4 parking spaces per household. Seattle has >5 per household. Other stats about parking density in the article...
https://www.fastcompany.com/90202222/heres-how-much-space-u-...
The very existence of slums/slumlords suggests that selling substandard housing to desperate people suggests both that there are people willing to accept substandard housing and that it is profitable. If it can work with rat and mold infestations, etc, it can work with an uncomfortably small amount of parking.
I have no idea what the right amount is, but I certainly don't believe your reasoning provides more information.
I somebody who paid for his house, pays his taxes, and votes, just like everybody else. I'm well within my rights to advocate for urban planning that meets my needs and desires.
Neighborhoods aren't static and there's ample evidence that current planning models are broken.
As for parking, consumers of the parking should be paying for it directly. "Free" street parking is not free and takes up considerable space. Parking minimums for many building types require an excess of parking that leaves vast asphalt pads empty most of the time.