I target simplicity by having one virtual environment instead of many and synchronizing dependencies instead with the main branch instead of... hell?

Have you tried deploying to hundreds or thousands of VMs? In my experience, managing container deployment and state is much easier, vs wrestling with inconsistent env state on compute for whatever reason.

For the life of me I don't understand how deploying to 10 machines is functionally different from deploying to a billion machines as the process is exactly the same. Unless you sabotaged your deployment machines with some manual meddling, it's the same with Docker images and Ansible.