OTOH, if there is always that much space available (and presumably there didn't used to be before the price hikes) then it is evidence that a lot of people have chosen to go elsewhere because parking became too expensive.
Can the location compete with that "elsewhere"? If it is a unique location with unique reasons to visit, probably yes. But if it is the typical old downtown with stores competing with the strip mall with similar stores but free parking, probably not.
I've seen the depressing cycle of multiple vibrant downtown cores become abandoned after parking meters came in. I very much prefer a strong active downtown core even if finding parking is a pain, to one that is mostly all boarded up and abandoned but there's plenty of paid parking.
If after the price increase there are 10% (50) parking spots open, that means at least a 100 people went elsewhere (20%). That's a pretty significant drop in business to the local stores.
And speculation aside, I've seen this happen in two downtowns I frequented. Parking meters were installed, people went elsewhere, the vibrant downtown died and was boarded up and abandoned. And it's not just a transfer of business to a different location, but a loss of cultural significance. Because the old downtown had artists and musicians who no longer have a place at the strip mall. The stores moved, but the culture was lost.
Your math ain't mathing.
... although if they were, the price of parking would be way higher. The optimal price for parking is a time-and-day-dependent price set high enough that around 10% of spots everywhere in the city are free at any given time, so that people who need parking can generally find it conveniently nearby to where they're going.