Network issues are hidden by the install script

See https://github.com/python-poetry/install.python-poetry.org/blob/385616cd90816622a087450643fba971d3b46d8c/install-poetry.py#L356-L369

The above configuration means "stdout to pipe, stderr matches stdout".
If you're having network issues, this installer either completely obscures or significantly delays the reporting of said errors.
I never let it run it completion, but the network issues were significant enough that it was running for several hours (this was with default configuration, outside of being behind an org proxy + pip.conf pointing to an org mirror of pypi).

Personally, I think it's fine just to log to the console all stdout and stderrr from PIP as it happens.
Might be good to log individual process stages of the environment's creation as well (so you can know if you have other issues with your system).

install-poetry.py の 356-369 行目から始め、インストーラーが pip の stdout と stderr をどのように取得して報告しているかを調べます。低速または失敗するネットワーク構成でその動作を再現し、そのうえで、pip の出力が生成されると同時に表示され、プロセスの各段階が有用な進捗情報を提供することを確認します。