It seems like TORCH_CUDA_ARCH_LIST is being ignored for me when I create the wheel:
I run:
  python3 setup.py clean --all
  time USE_STATIC_CUDNN=1 USE_STATIC_NCCL=1 ATEN_STATIC_CUDA=1 USE_CUDA_STATIC_LINK=1 \
       TORCH_CUDA_ARCH_LIST="5.2;6.1;7.0;7.5+PTX" \
       CXXFLAGS="-stdlib=libstdc++" \
       python3 setup.py bdist_wheel -d "${BUILD_DIR}"

but the results show:
./cuobjdump libtorch_cuda.so -lelf | awk -F. '{print $3}' | sort -u
cubin
sm_35
sm_37
sm_50
sm_52
sm_60
sm_61
sm_70
sm_75
sm_80

I also got an interesting warning.  Is this relevant?

CMake Warning at cmake/External/nccl.cmake:65 (message):
Objcopy version is too old to support NCCL library slimming