You can visit your local park hopefully you live in an area with one. You can invest time using transit to get to another park. Traveling during rush hour would be difficult. Traveling with many children or younger children adds a difficulty. Being disabled or older or worse disabled with children more difficult. For the young, childless, plenty of time on their hands or live next to a park of course walking a few steps is a no brainer.

But it's like buying a gym membership across town with the idea that you would walk everyday. You aren't going once winter hits.

Not American but have been young and took transit and walked everywhere but also seen seniors in wheelchairs who stopped going to the park after they stopped allowing cars to park.