> So the best way to get more people in a sports stadium would be to get rid of the parking lot
The googling is taking too long for me to get numbers, but I'd be willing to bet that most stadiums have enough seating capacity that, if you were to pack every single space in their actual parking lots with cars, you'd completely fail to fill it up.
> or walmart's sales would go up if they got rid of their parking lots?
Walmart is a special case in that it's built around people who have cars: you don't go to a Walmart to buy only what you can carry. You go there to buy as much as you can so that you can avoid shopping for the rest of the week.
But around here, Pike Place Market? Westlake Center? Pacific Place? Yeah. Most of their business comes from the fact that they're within walking distance from the Financial District and the Convention Center. Uwajimaya? Benefits immensely from the fact that it's located in Chinatown, where its main market is; I'm two blocks from it and I pick up something every other day on my way home from work.
(Actually, Uwajimaya is brilliant in that it has apartments on top and parking below. A lot of residents are literally walking through the store to go home.)
> Or on a small scale, I'd be more likely to go to a restaurant or small retailer if I knew for certain I couldn't get there on foot and if I drove there, I wouldn't be able to park?
No, you're reversing it. The question is about how many more customers a restaurant or small retailer would get. I didn't fully explain: it starts by recognizing that the number of customers you get is a percentage of the number of potential customers you get. If you already knew about that restaurant 50 miles out, then obviously, the only thing that matters is that you can get there. That's a transit issue: can you get to point B from point A in a reasonable amount of time, for a given understanding of reasonable. Some people cannot imagine reasonable amounts of time via public transit, so they cannot conceive of transit without cars.
That's a different problem. The problem here is that, using a "cars = customers" model, you have two facts: (a) most people don't look at the storefronts as they drive by. They're actually looking for parking. Your parking space is a loss leader in order to get them to look at what you're selling in the first place, on their way somewhere else. And (b), people don't know you exist until they see you.
If you already knew about it, then it's more akin to parking at your office. You have no need for discoverability, just availability. If you had magical public transit that was equally fast, you could use it instead and poof. No need for cars at all. The merits of cars versus other things isn't customers; it's speed.
> I've seen poor parts of downtown with empty sidewalks and boarded up storefronts. Must be the parking lots?
In short, yes. What if those parking lots were cheap housing instead? You wouldn't need a car to get there, and you could walk across the street to shop.
This isn't a silver bullet "delete parking lots = magically better". It's a functional component of many other much larger, much more complex solutions. I'm telling you why the component is being included--namely the space efficiency of pedestrians equals a higher customer base--but that isn't a complete solution by any means.
I mentioned a and b earlier. There is a c.
Anytime your parking lot isn't nearly full during business hours, you have a problem.
Why? The reason that cars = customers is because cars forcibly disallow anyone else from being a customer. When you design your street for cars, you discourage pedestrians: especially the window shoppers. When you design your neighborhoods to be zoned between residential and commerce, you make it impossible to reach businesses except by car or long-distance public transit.
My grandparents live in a suburban cul-de-sac in the Bay Area. Pretty place. Very calm and peaceful. And they're lonely. My parents and uncles and aunts have to regularly drive in from across town to visit with them. Couldn't they go down to the local store, rather than asking a son or daughter-in-law to buy groceries? Nope. They're too frail to drive, and walking the massive block to the huge nearby intersection, and then walking across the vast expanse of asphalt to the nearby Lucky's is basically impossible. Hell, I hate doing it and I jog the whole thing for fun. There isn't even anything on the way to stop at. There's like... one bench for the bus stop. A Radio Shack on the other side of the 3-lane road. There are actually quite a few other options; they're just even further away.
You basically need a car to get to what is technically a block and a half away, if we count by intersection. My god-grandparents would be in a similar situation, but they're able to drive, so they can do the 20 or so blocks it takes to get to the Asian market.
It wasn't always a Lucky's. It used to be an Albertson's, I think. And it was something else before that. That parking space keeps them alive, sure. That's about it. No one goes there unless they have to.
(And if I'd spent the time googling rather than typing up these anecdotes, maybe I would have found some damn numbers.)