I wonder though if it's enticing enough to leave Emacs' versatile configurability and introspection abilities behind. I don't think Zed has any way to extend its behavior beyond configuration options, and if it doesn't have a scripting language to go with it now, then it seems quite unlikely it will have a good one in the future either.
I guess there are different hats emacs users wear, or things that are in Emacs' favour.
e.g. in terms of "Emacs is just a good tool", it's very good at being a keyboard-driven tool.
If these fancy features like multiplayer catch on, I'd expect someone would figure out a way to do something like that in Emacs.
It's probably due to Emacs being so customisable that allowed it to get Magit, which is an outstandingly good user interface for Git.