YMMV significantly depending on the specific metro area. The suburbs of Seattle like Bellevue and Richmond were like that too - full of large parks and natural reserves everywhere.
https://www.alltrails.com/lists/san-diego-canyons
If San Diego was as wet as some European cities, those would all be amazingly green.
Redmond?
Then there are also much bigger parks with some hiking trails through more natural/unmanaged areas like griffith park or the sepulveda dam area or the hansen dam area, that also have all of these amenities (save for the holocaust museum) and even more. Sepulveda dam has archery, a rocket launch pad, and a model aircraft field. Hansen dam also has the archery but also a lot of equestrian activity and people keep horses in the area.
To act like the greenspace is not available or unusuable doesn't speak to what is actually there for use today.
> […] but not an actually useful park beyond sitting with a book or a smoke perhaps
Yes, and grass to play improvised football or things like it.
> chock full of amenities europeans would be lucky to have
Not really, because European social life is not organized-activity-oriented. At least nowhere near my perception of American life (8y in CA).
In Europe, you meet first (let’s hang out, meet at a cafe, in the park) and then roam around and maybe do something spontaneous. In many cases, this involves mixed ages (kids playing, grandparents etc).
> Bathrooms
Yes. To be fair, I think it depends on how urban it is. In bigger parks like Golden Gate Park SF, the homeless don’t bother to go that far. If you have bathrooms near urban centers they tend to get misused and scare away regular folks anyways.
> To act like the greenspace is not available or unusuable doesn't speak to what is actually there for use today.
The green space in the US wins overall (again based on mostly CA), if you commit to the car ride to get there. In fact, if you count the national/state parks it might be best in the world.
In terms of green space integrated into urban life, I would say Europe is way better. In the US you can’t easily “integrate” green space that way into car-centric urban sprawl, because everything is already compartmentalized and divided and driving distance afar from other parts.
Comparing the LA metro area to almost any European city, it's stark how much more unused or usable green space there is in Europe. The US seems much more binary – you're either in a city, or you're outside one, it's not like the US is lacking green space at a national level!