I'd imagine there's a lot less motivation to build new physical recreation spaces like skateboards etc if almost everyone is starting at a screen every waking minute.
It isn't like they were really building these places before smartphones, though. These are things that are generally either services and cost money rather than make them or they are for-profit places that don't always have much demand. I don't know why it seems surprising that the "motivation" to build these isn't there now since the same restraints are still there.
I agree. Local skateboarding places that are free get pretty well-used. Hiking is still popular but requires a bit more time unless you live near somewhere suitable.
Part of the problem is so many people don't have free time and/or money to do anything more than scroll on their phones. That goes for people with good career jobs with long hours, and those scrolling on the bus as they go from one of their low paid part time jobs to another.
At the same time, appearances are more important than ever, so it might make business sense to sell equipment to people who want to pose with them. Same with rec spaces too, people don't actually have to partake in the activities, they just have to pay for the membership (and the tagging rights)