It’s Chrome’s fault really. That’s who Mozilla are afraid of.
It came on the market and surpassed them in no time. It forced them into adopting a weird versioning system - I’m pretty sure they did it in a misguided attempt to compete with Chrome’s rapid “major” releases.
So yes, they are very much afraid they’ll lose even more market share and they may be right.
(I’m not making excuses - I hate this as much as anyone here and I’m typing this in Firefox)