Firefox without XUL

People keep telling Firefox is going to cease to exist the moment it forbids using XUL (old API) addons. But is that a fact? I tried to find an addon that would be impossible in Chrome/WebExtensions and couldn't come up with anything substantial! There is even a Chrome alternative to TreeStyleTabs! The only addon I could think of that won't (probably) be feasible is Vimperator.
So I would like to ask you, user, what important addons won't be possible anymore with WebExtensions?
Is it really as bad as some people say?

Bump.

One more bump.

Downthemall

But there are download managers for Chrome, e.g. Chrono Download Manager. Are you sure Downthemall is impossible to implement with WebExtensions?

Everything will be fine and the naysayers will still be using FF when the fire dies down!

>Are you sure Downthemall is impossible to implement
The question isn't necessarily if it's possible, rather if it will get written. The DTA dev has said he won't re-implement it.

Yeah, I heard about it, too. Same w/ Quicksaver, the author of TabGroups, FindBar Tweak, Beyond Australis, OmniSidebar and Puzzle Bars.
However, I'm more curious if it's doable to implement it. If so, i might rewrite a couple of extensions myself.

But user, Pale Moon supports supports the addons anons are used to, why use Firefox?

the reason people use FF is its extensive customization and extensibility

The reason it has that is because of the community of volunteers and hoobyists developing themes and extensions for free

Mozilla kicked those people in the dick with electrolysis

And now they're kicking them in the dick again, even harder

those people will leave

firefox's raison d' etre leaves with them