I took a landscape architecture class in college and we had a section on designing playgrounds. Most playgrounds are designed with equipment that mimics animals or pirate ships, stuff from children stories. However, abstract shapes and equipment are actually better for children as they allow the brain to create story's and imagine what the equipment could be. So the brutalist playgrounds you posted would actually be ideal.
That's an interesting theory, but what do the children think about it? It sounds like something a psychologist might come up with, I can't imagine many parents would design a playground using abstract shapes and concrete.However, abstract shapes and equipment are actually better for children as they allow the brain to create story's and imagine what the equipment could be.
Depends how old you are. In the 80s there was lots of this type of shit. Parks liked big conrete behemoths, because they don't really require any maintenance, and they kind of look sculptural by nature. Then parents got whiny and litigious about little Johnny breaking his teeth on the concrete and they disappeared quickly in favor of those plastic monstrosities.
It was 3 or 4 years ago so I dont remember the sources but it was based on research about the stimulating effects of different playground equipment . I do remember they talked about this "park" in Queens that was just an lot with dirt mounds and a hole with water in it and it was kids favorite playground.