There are two ways to solve migration problems like this: reduce the friction, or provide a carrot (meaningful benefit).
Conda has provided the carrot already, and it works. Generally well enough to overcome the friction (though not always - see the quotes I posted above).
What we’re actually seeing is frustration among non-conda users who don’t have that carrot, but not badly enough to overcome the friction. And the closer people get to isolated, working package installs without needing conda, the more fiction is created.
In short, the “grow up story” from venv-based tools is weak, because you have nowhere to go without restarting. It’s not on any other package manager to solve this - they’re totally free to say “yeah we told you the mistake was right at the start when you relied on the system install, but we’re glad you’re here now, let’s get to work”. They don’t in any way have to pick up where venv-based tools give up and go from there if their argument is that venv was the original problem.
(conda and other system package managers are all interchangeable here. Nobody expects apt/yum to install packages that will Just Work into your highly customised venv, right?)