macでThe path /usr/local/bin/python3 (from –python=/usr/local/bin/python3) does not exist
下記でどこのpythonが使われているか確認して
$ which python3
/Users/a/.pyenv/shims/python3
使われてるpythonで仮想環境を作る
mkvirtualenv --no-site-package --python /Users/ha/.pyenv/shims/python3 env1