Why don't purely functional languages use reference counting?

Question

In purely functional languages, data is immutable. With reference counting, creating a reference cycle requires changing already created data. It seems like purely functional la

Answer 1

Reference counting is MUCH slower than GC because it's not good for CPU. And GC most of the time can wait for idle time and also GC can be concurrent (on another thread). So that's the problem - GC is least evil and lots of tries shown that.