But the system is not a workspace acts like resources are free. Everything that’s wrong with a modern computer being slower than one from 30 years ago at running user applications has its roots in this kind of thing. It’s more obvious on mobile devices but desktops still suffer. Android needs more RAM and had worse power utilization until a lot was done to move toward native compiled code and background process control. Meanwhile Electron apps think it’s okay to run multiple copies of Javascript environments like working RAM is free and performance isn’t hurt.
Perhaps, but that's not really relevant here. Python's virtualenvs wouldn't increase RAM usage any more than using the system-wide environment.