What I've heard — and I don't claim any real expertise — is that the city was built by a significant amount of private money and certainly private companies, and what made the city fail was several different governments all deciding that they didn't want this sort of thing, specifically China wanting houses to not be investments and restricting how much money Chinese citizens could take out of the country, while Malaysia started off in favour of it but then decided that "foreigners" (which in the face of Forest City would have been Chinese) shouldn't be buying up housing in Malaysia.

That's not really a sign of central planning failure, any more than, say, California City — failure, sure, but not due to what distinguishes economic central planning from capitalist diversity's self-balancing.

https://en.wikipedia.org/wiki/California_City,_California