All modern Objective-C codebases and a high percentage of large C++ codebases use refcounting without a cycle collector. Some of them have memory leaks, and there are some quite ugly cases like [1], but most of them have it under control. So it's not like relying on pure refcounting is impractical in the real world; it's just a bit more difficult to deal with than full GC.

[1] http://albertodebortoli.github.io/blog/2013/08/03/objective-...