Years ago I lived on $40 per month, after building my own cabin in Oregon -- wood heat, kerosene lanterns. Then I bought an Apple II and things got more complicated (https://www.atariarchives.org/deli/cottage_computer_programm...). But basically I agree with you. Most people will never have that much, or need it.
Nowadays Firefox is just a poor Chrome knockoff with no distinguishing features. As a casual user who switches but is unaware of add-ons/etc, Firefox gives you nothing, so why would you switch?
Firefox can reinvent itself and regain marketshare by shipping actually useful features like built-in ad & distraction blocking, but chooses not to.