The most efficient workflow I've found for pip so far is something along the lines of:

  pip-compile # resolve and pin the dependency tree
  grep '==' requirements-pinned.txt | xargs -n1 pip wheel  # build every wheel in parallel
  pip install *.whl  # install the pre-built wheels

It may not avoid all the slowness, but when nicely integrated into a build/CI system it can avoid suffering it more than once.