Lisp is a wonderful language (Common Lisp in particular, but I am dabbling in Scheme now too), and absolutely fantastic for web development - seriously people should give it a chance in that space, I would totally develop any SPA in Lisp[1].

QuickLisp is simply a joy to use, and the language is very portable with a fantastic specification and many top notch compilers.

IMO, what holds it back is a lack of a top notch IDE. It took me a year of love & hate with Emacs, I can now make pretty good use of the amazing software that is Emacs (where everything can be changed), but honestly at times I want a simple point & click free IDE which is polished and does most things well and out of the box. Portacle is a step in the right direction, but the Emacs dependency IMO does make the language a bit more niche and lose out to other languages for beginners. If some big corporation can mix sublime with slime with paredit with some of the customize ability of Emacs, then Common Lisp could explode in popularity.

Don’t get me wrong - I LOVE Emacs and everything about Emacs & CL combined, but it took me a year to get to this point.

[1] For those interested, I wrote this article covering the basics: https://ashok-khanna.medium.com/lisp-the-web-4c00c88d11f9

The emacs bias is even part of Lisp advocates mental models, so it's no surprise that a lot of would-be Lispers give up at the thought of having to use it. But there are alternatives, and it might be fruitful for advocates to routinely point them out. vim (my preference) has two slime plugins that work really well, Atom has https://atom.io/packages/slima and as you point out there's lots of Emacs-variants. There's also lem and Second-Climacs might one day be good. And of course there's the two proprietary IDEs with LispWorks and Allegro that both provide trial versions to see if you like them before shelling out money.

Apart from editors, more editor-independent tools would be nice. McCLIM's Clouseau is a pretty cool graphical inspector/variable watcher.

IMO what holds it back is lack of a big company using and promoting it along with tooling (which might be in the form of alternate IDEs or good plugins for popular editors like VS Code or IntelliJ). Clojure has shown what's possible without such, most use emacs but there are popular alternatives too, and for a time it was even as popular as Go, but Go has BigCo backing, and we can see how much further that brought it despite its many shortcomings.

Do any non-emacses have anything like paredit?

https://susam.in/blog/lisp-in-vim-with-slimv-or-vlime/ is a good overview of the differences between slimv and vlime (the two vim plugins) and how to use them.