I cannot continue working on my add-ons

I don't expect much from the leadership who brought us FirefoxOS, and indeed the WebExtension migration is being mismanaged - BUT: the hard truth is that the Chrome extension ecosystem is already on top and growing, while the Firefox one has been waning for a while.

If you build a browser extension today, you build it for Chrome; if you have a Mac, you also get a Safari version almost for free; and then eventually, if you have time, if you can be bothered, you port it to FF. This could not go on, something had to be done. And they did it: JetPack/Webextensions, despite the uber-confused documentation, is an almost-complete compatibility layer that makes porting extensions from Chrome much easier. If they'd left it at that, nobody would have complained.

Unfortunately, the next step is to gut the old infrastructure. They might have their technical reasons for that, but it seems a suicidal move from a commercial perspective. They are throwing overboard almost 20 years of competitive differentiation and community engagement. It's like Microsoft told people to rewrite their .Net apps in ObjC.

There seem to be a lot of people that are saying "oh, without XUL based extensions, Firefox is just a (worse) Chrome clone, so I might as well just use Chrome."

I think what they might be missing is that Mozilla's conclusion is a lot like the people seem to be thinking here -- even though Chrome doesn't have the fancy extensions that are possible in Firefox, many many more people are using Chrome than Firefox, because they see it as a better Firefox.

Clearly, that has something to do with either security or performance, where Firefox has a perceived lag.

Mozilla is actively working to improve performance, and you may not want to switch to Chrome after all, because Chrome may instead be the poor man's Firefox (I personally think this is already the case, simply because with my 679 open tabs, Chrome would simply kill itself [44 loaded]).

This video is one of the most exciting I have seen with regards to web browser performance, and it's Mozilla:

https://www.youtube.com/watch?v=an5abNFba4Q

More info on what this means for Firefox:

https://wiki.mozilla.org/Quantum

TL;DR: What if even with the missing XUL extensions, you wouldn't want to switch to Chrome, because Firefox was just plain faster?

Having more addons available for more browsers is good for the open web, even if these browsers aren't specifically Mozilla's.

>>Clearly, that has something to do with either security or performance, where Firefox has a perceived lag.

This is completely false

It has something to do with MARKETING and the fact the Google is largest marketing company in the world and has the ability to market chrome far far far more effectively than Firefox

IE is crap, so Windows users seek a replacement for IE, use to their only option was Firefox. Once Chrome came on the market with a HUGE marketing push people started to migrate

It was 80-90% marketing, not technical

Even if Firefox is better preforming people are not going to switch as only Technical people give a shit about performance numbers.

Edge on windows 10 is starting to eat into Chrome partly because MS is bringing back the IE6 marketing and integration tactics that got them in Anti-trust hot water in the 90's

No Firefox, absent Google Discontinuing the chrome Browser, will never break 20% market share again, I do not care how must better it preforms.

Mozilla needs to focus on Power Users, and Privacy. They are failing at both with these moves IMO

>>you wouldn't want to switch to Chrome, because Firefox was just plain faster?

They they take away my TreeStyle Tabs and a few other Extensions I dont care how much faster it is, FF will be removed my all my systems

TreeStyle Tabs is the the Main reason I use FF today. I dont understand why browsers have tabs horizontally across the window, it looks stupid and is unusable once you get above 20 or 30 tabs open So you talk about have 100's of tabs open, it is pointless if I do not have TreeStyle or some kind of Vertical Tabs. And no the Stupid Dock style of doing it on Chrome and other WebExtensions based hack is neither desirable or usable

Ubiquity https://en.wikipedia.org/wiki/Ubiquity_(Firefox) (now defunct) had natural-language commands with localization including subject/verb/object order. It supported subscribing to commands too, so you could keep up with changing APIs automatically. It even understood pronouns, so you could write "email this to Dave" and it would email your selected text to your gmail contact named Dave. The only thing it was missing was a permissions model to limit what untrusted command code could do.