This is a great article but it saddens me that it had to be written because all these years later, community members are still mad their extensions don’t work.

I guess I’ve underestimated all these years that what David described as the problems with XUL and the reasons it had to go away weren’t commonly understood. As the post states, it was clear as far back as 2010 (and honestly earlier), that XUL extensions were both Firefox's killer feature and also the reason that it got its ass kicked by Chrome (and to a lesser-extent, Safari). Extensions were amazing but the tax it created for performance, development, and security ended up becoming what made the browser so slow. Chrome and Safari didn’t have extensions but they had speed and built-in features that replicated many of the most popular extensions. And once Chrome added extensions support — and support that didn’t require that add-on development tax — it was over.

I found this bit of the post really telling:

> And yet, there was no choice for Mozilla. Every day that Mozilla didn’t ship Electrolysis was one day that Chrome was simply better in terms of architecture, safety and security. Unfortunately, Mozilla delayed Electrolysis by years, in part because of the illusion that the Firefox benchmarks were better enough that it wouldn’t matter for a long time, in part because we decided to test-drive Electrolysis with FirefoxOS before Firefox itself, but mostly because we did not want to lose all these add-ons.

>In the end, Mozilla decided to introduce WebExtensions and finally make the jump towards e10s as part of the Quantum Project. We had lost years of development that we would never recover.

This aligns with what has always been my personal view which is that Mozilla waited too long to make the changes it needed to compete with Chrome and by the time it finally did the hard thing and lose extensions and start over.

When you consider that there was still time after Chrome was released but before Quantum where IE had the largest browser share (it wasn’t a long period of time post-Chrome, but it existed), that’s indicates to me that there was time both before and after Chrome's introduction for Mozilla to rip the band-aid off and drop XUL for the greater good of the browser. After all, IE didn’t have extensions in any comprehensive way, which could have given Firefox to refactor and approach. Sadly, Mozilla waited too long.

But what really makes me sad is that there are still diehards mad that XUL died. When to me, we should all be angrier that it was allowed to live as long as it did.