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.
Appologies, I am not a tax auditor, I don't have enough spare time to go comb through mozilla's finances to list out every single expense mozilla has. If mozilla can't make do on that funding, they maybe they deserve to shut it's doors for good afterall.