Why doesn't UE utilize STL containers?

I’m really looking forward to UE switching to STD, and with like any proper sexually transmittable disease, perform poorer and die off until it is rid of it.
Specialized solutions are always a better choice than a general purpose one, every proper game engine has its own implementation of a standard library and its own custom memory allocation system because it fits the “real time / high performance / data driven” software, which is games, better.