Yes. Mozilla has let firefox rot. Firefox can't even do tasks like render gradients properly (examples of such issue https://play.tailwindcss.com/9hekptcy9b https://codepen.io/art-solopov/pen/VYwwdBK. and refuse to implement stuff like webusb despite the fact that it can be done in privacy friendly ways.

I don't think firefox is a lost cause, but I do think mozilla is a lost cause. I have little hope that mozilla will right the ship, but sometimes things happen that do give me hope.

I do think gecko is quite frankly a bad platform, there is indeed a reason why so many things use blink/chromium as a base and not gecko, is it possible to make gecko into a suitable alternative? sure, but mozilla hasn't gotten even remotely close.