But Google, in contrast to Mozilla, has to work hard to innovate and their income is always a reflection of how good they are and they have a management with a long-term vision.
Due to the fixed contract Mozilla will not feel the consequences of their actions for a very long time.
You see this kind of laziness everywhere when money doesn't matter anymore. It is more or less human nature.
To answer your question: It is not about marketshare. Mozilla has always said it is about values and open source, and so on. They could do something great even with 1% marketshare.
Mozilla is basically doing nothing that makes power users say "Wow, I really want to use this browser and will recommend it to my friends and family". Instead for some reason those users are increasingly frustrated with Firefox on multiple levels.
I think there is a slight possibility that the end of 2019 or the beginning of 2020 will be when you see some subtle changes to how Firefox works. Maybe they get their humility back.