GC is a no-go, as it causes unacceptable frame-rate dips. The kind of people who buy 120Hz screens are unlikely to be impressed. Even Shenandoah etc. are very unlikely to fix that.
To be fair, every application is going to differ, and perhaps games need tighter control of memory than a high performance GC is capable of, but automatic GC does make programming a lot easier.
Does it, though? I've played titles written in Java and achieved smooth 60 fps back in 2008.
Second, to my knowledge it's still very cumbersome to avoid GC allocations in Java. By comparison, it's easy to reduce calls to global heap allocators in C.
Second, it is relatively easy to do native memory allocation in Java, but apparently people keep forgetting to learn their toolbox properly.
Third, calling malloc() is such an issue that there used to be companies specialised in selling optimised versions of malloc()/free().