Presumably, "major" means "used by most people", and even without checking I'm quite sure that if you looks at the install numbers of old Firefox for Android Add-ons, you'll find that a very large part of those installs were of extensions that are still available.
Sure, I'd like my small Hacker News extension to be available as well, but I do care far more about uBlock and Privacy Badger being available - and judging by installs, so do loads of other people.
(Again, which is not to say that I'd like the smaller extensions to be available as well. But "the major addons that people use are available" looks like a mostly accurate claim.)
This is actually a small portion of addons available in the desktop Firefox. Many of them somehow worked, but were never optimized for mobile. "Worked flawlessly" is in my opinion a great overestimation.
I beg your pardon? Literally hundreds if not thousands of add-ons worked flawlessly on Firefox Android until a few weeks ago.
> All the major addons that people use are available
You'll need to seriously find some source for that extraordinary claim. What does "major" even mean? Who cares about "major ones" if 50% of my add-ons are missing, crippling the functionality of my browser on mobile? This claims makes no sense at all.