I just enumerated the playgrounds our exurb and ALL except 1 have at least one of the things you mentioned. Most have both monkey bars and swings. The exceptio

I just enumerated the playgrounds our exurb and ALL except 1 have at least one of the things you mentioned. Most have both monkey bars and swings. The exception is a splash pad playground, so not really indicative of any sort of trend (except perhaps that our summers got a lot hotter over the last 20 years). There are parks that do not have any playground, but those are mostly either dedicated sports fields, "adult-oriented parks" (eg the city commons), or nature-oriented parks (with trails, trees, and water). So not the sort of parks that ever had playgrounds in the first place. Additionally, we now have some parks with natural climbing walls that you need to bring ropes to use, which is quite a bit less safe than marry-go-rounds and what-not. (I've never seen them used without adult involvement, but TBF a fall from the top would probably actually kill/seriously harm a kid).