Note this part:

> That said, background processes invoked from Eshell can be controlled the same way as any other background process in Emacs

I haven't used Eshell much, but this makes a simple "command &" arguably much saner than in a traditional Unix shell.

I imagine that a new feature would be accepted only if someone can make it play nice with existing features. And in case of job control, I have a bad feeling about the complexity involved.

I think it comes down to that emacs itself has facilities for managing the background processes, and eshell in general tends to defer back to the surrounding editor for a lot of functionality.

So if there's an "emacs" way of doing things, generally eshell delegates to that, instead of rolling its own.