It may kill Mozilla, no reason to say it will kill Firefox itself. Perhaps Firefox would flourish a lot more if it is finally released from Mozilla's clutches.
I don’t think Firefox survives as a community based project.
cf. Mozilla Firefox Is Dying (2025) https://news.ycombinator.com/item?id=44939271 and a list of posts from 2024 https://news.ycombinator.com/item?id=39303736