I could see that, since Firefox rarely (if ever) crashes, due to an add-on, during the time of 2019-2025 where they fully migrated to WebExtensions(Couldn't find a single incident between this time that crashed the entire browser. Everything else was related to either crashing the complicated add-ons, like uBlock and uMatrix, or some misconfigurations in the OS, like what happened in NixOS). Pale Moon, on the other hand, suffers a lot of crashes, like what happens from the infamous NoScript add-on, DeCDN crashed the browser on an Image-heavy page, and many more undocumented crashes by some add-on on Pale Moon.[*]very quickly, add-on developers realized that anything they did could break anything else in the system, including other add-ons and Firefox itself, and they often had no way to prevent this
[*]similarly, anything Firefox developers did could break add-ons, and they often had no way to prevent this
This issue, if not being seen right now, it could be more present in later years, when Pale moon addons gets updated with more and more lines of codes to accommodate to today's modern web that is already heavy on the modern web browsers. Eventually, Pale Moon add-on developers will start to face more hiccups and try to find a workaround on Pale Moon and keep up with the standards of the web and then there also could be a risk of Pale Moon updating its browser and engine and all of the sudden their addon crashes the browser, because some features that it asks for are no longer present and....If you were writing XUL-based add-ons, you quickly realized that preventing it from breaking stuff was… complicated. Several add-ons could modify the same part of the user interface, resulting in odd results. Several add-ons could accidentally inject JavaScript functions with the same name, or with the same name as an existing function, causing all sorts of breakages.
These issues seems to be inevitable, and this could be the main reason why Firefox just went with WebExtension (I'm not denying the possibility that it could've also done so, because uncle Google demanded so.), They made Jetpack, and according to the blog, they had the idea, even before Firefox was called Firefox. They already had the intentions and they knew how problematic the XUL addons would be in the future.
These issues would show up on Pale Moon and over the course of the time it would be more visible and bigger of a hurdle for the developers to deal with it. (Not to mention that the majority of the currently used addons that we have right now is barely being maintained, let alone each addon maintainer would cooperate with each other to have their addons not break when bundled together) Even some addons, when they're getting forked to Pale Moon, the maintainer themselves have no hope that it would be on the same performance as the original counterpart, like what uBlock origin addon developer has said.
I know that Pale Moon doesn't plan to introduce WebExtensions to its engine, but are we all really going to a path, where all of us are gonna deal with so many issues, that there even could be some core developers who would quit in the middle of it (I'm not saying names, but you already know who was one of the core developers who decided to leave at one point, back in 2022)? Are we gonna be used as a reference by Mozilla as "See?! This is why we abandoned XUL."?