std::thread does not include support for priorities, controlling the size of the thread stack, controlling the scheduling policy, or controlling the processor affinity.
Scheduling class and priorities are crucial for real-time systems. Processor affinity and stack size are really important for high-performance systems. Such applications will either continue to use the native thread facilities, maybe in addition to std::thread, maybe instead of std::thread, maybe through vendor extensions that expose the needed features along with std::thread.