At some point they will hit a Trust Thermocline, if they haven't already:
https://every.to/p/breaching-the-trust-thermocline-is-the-biggest-hidden-risk-in-business

This is a great moment for someone to come in and offer what Mozilla's the soon-to-be-former core audience is looking for.

And that core audience will then promote it among their friends and family, on their campuses, and in their workplaces.

Exactly the same way Firefox was being promoted, very successfully, when the Web was young.