Some modes also support limited refactoring tools[2], but that's not quite as common.
[1] https://www.gnu.org/software/emacs/manual/html_node/emacs/Xr...
[2] https://github.com/clojure-emacs/clj-refactor.el, https://github.com/Wilfred/emacs-refactor, https://www.emacswiki.org/emacs/SemanticRefactor
It's a great time to be alive
Happy sigh...those were the days :-)
It's hard to beat an IDE on a large, disorganised codebase though, I'd lie if I said I only use Emacs and never reach out for an IDE.
It's not as sophisticated as an IDE, but it works with practically any language and is easy to customize.
I find it often quicker than an IDE..
What they usually can't do is the more involved stuff, like refactoring, because there is no company who pays people to implement these for emacs/vim.
It's true that funding is important. CIDER has benefited from this system: https://www.clojuriststogether.org/projects/