You don't have to activate the environment. I never do; it's a strictly optional convenience (it you think it's convenient).
Instead, simply run the interpreter installed in the environment when you run your app, e.g. "./my_env/bin/python my_app.py", and things will just work. No activation required, no special mode, nothing to forget.
The part about requirements.txt and installing packages could also be simplified if you did it the other way around: install first and create the requirements file from that:
Most of the steps you're listing take only a few seconds. They're talking about the actual management, not how long it takes you to type . venv/bin/activate
Maven is far more complicated and burdensome when compared to virtualenv and pip... pom.xml, what a righteous mess of XML and overly specified nonsense.
Maven Scala project - create skeleton, add libraries to POM, write app, run app
PIP Venv Python project - create venv, enable venv, create requirements file, write app, run pip to install dependencies(possibly install GCC and extra libraries), run app
(Oh... and god forbid that you forget to deactivate venv)
You're lying when you say that library management is easier in Python. It's just factually untrue.