This smacks of the https://en.wikipedia.org/wiki/The_Innovator%27s_Dilemma. If we're afraid that people will want to write packages in Blub for some reason, and we refuse to accommodate Blub at all, we're just driving everyone to some other editor that embraces it.
I think the difference is that Emacs isn't a company, and it doesn't need to beat others in a competition, it just needs enough contributors to keep moving forward. Not everyone needs to use Emacs for Emacs to succeed in its goals.
True, I was thinking of http://www.paulgraham.com/avg.html (where Lisp was Viaweb's "secret weapon"). And I'm worried about Emacs ending up with too small an audience of package maintainers to cover mainstream workplace use cases.