Encountered a paywall so apologies if missing some context, but when you say free time do you mean they live far away and need to drive distances to parks?
I’m American and I’m outside all the time. Walking the dog, or walking with my family, taking my daughter to the playground. I work full time and have a family but easily have time to walk every day.
But maybe “outdoors” here means activities like hiking? If so I think I understand what you mean. That would be something most people could only do on weekends.