Well, for example, there is no major OS that brings Firefox bundled with it. So they have to keep creating something good or people will stop using it. Therefor

Well, for example, there is no major OS that brings Firefox bundled with it. So they have to keep creating something good or people will stop using it. Therefore, getting into a monopoly position is kinda hard for the Mozilla guys. Browser monopolies are bad because the ruling browser's implementation will always compete with the web standards.