At least for now, no, it is not possible. I agree that what you describe is how it ought to work in an ideal world, but it would probably require some serious rethinking of macOS UI/UX in order to make it work. For instance, it is not obvious what’s the best way to transfer the dock and the menu bar to a screen-less environment.

A hybrid solution I would love to see would be to have the current virtual screen, but with the option of dragging individual windows out of the screen.