I'm definitely in favor of this. This is much simpler than the virtualenvs we currently deal with. The only downside I can see is that virtualenvs also manage the python version, so there could potentially be some confusion as to which version to use. To build a virtualenv you need to choose a version as well, but at least once you do, it becomes explicit. Coming back to a project months or years later and then trying to figure out what python the project wants is minor but nevertheless an inconvenience.
Most other languages have moved that sort of information into more shared container formats like Docker (and higher level container orchestrators like Kubernetes, etc). virtualenv has been a relatively poor, Python-specific Docker, and it is probably past time for the benefit of Python DevOps to retire virtualenv entirely for more general/shareable tools.
I actually kinda liked having a virtualenv.
Although the hacks used to make it work, were not nice.
I would have loved to see core python suppport for virtualenv, which could probably avoid these hacks.
"Core support" in which sense exactly? It is part of the standard library: https://docs.python.org/3.7/library/venv.html