> It is really easy for a Downtown to go into a downward spiral if you take away the ability of people to get there.

I've seen this sad downward spiral multiple times, it is not a good outcome.

I used to live not too far from a town with a mellow but nice downtown center. Not a huge draw but many small nice restaurants and shops and there was steady business. Sensing a profit machine, the city filled all streets with parking meters. Turns out that while it was a nice area, it wasn't so irreplaceable, so nobody goes anymore. Business collapsed. I drove by last summer and everything is closed, the parking meters sit empty.

Same is happening now to the downtown one town over. It used to very vibrant awesome downtown, although small. Bars, restaurants, music venues, fun shops. I was there every night for something or other. Loved it. Easy free parking around. Some of the parking lots have office buildings now and the city lots have become very expensive. Much less activity there now, about a third of the venues are closed and the remaining ones are saying they can't last very long with fewer people going. While in its heyday this downtown was far more active than my first example, turns out it wasn't irreplaceable either. People just don't go anymore.

Point is that this tactic works only when the downtown is so established and so dense that people are going to go anyway even if parking is hard, like Manhattan.

Has there ever been a situation where taking away parking has lead to traffic dropping?

I've heard this, but I've never seen an example in practice. It seems like making things more walkable and bikeable, at the expense of cars, always increases foot-traffic, with no exception.

Good point. And 'yard', if any. You can even see this at large events that are in urban centers.

Churchill Downs for example is surrounded by residential properties. At Derby time a lot of those enterprising people would let you park in their yard for $5 or $10 (maybe more now, it's been many years). These are not large properties - typical older shotgun houses. I seem to remember them getting 10 or more cars and that's not even counting the space the house itself is taking up.

Sure, but this is why it makes sense to do it gradually. Things get built slowly and if the new buildings are taller they may actually take up less space (per person) than a car does, when considering ingress, egress, the road itself, etc.