Firefox the browser is still a great piece of software, literally unique, and also open-source.

Do you think any other company / organization would be able to take over it / fork it and develop it adequately? If so, where would they get the money? Many high-profile open-source projects (e.g. Python, Blender, well, Linux itself) managed to secure corporate sponsorships or donations in a much less toxic way than the Mozilla-Google deal.