Because Safari's not up to snuff and also because Firefox should also be able to compete. If you block browsers based on Chrome's dominance, Chrome effectively

Because Safari's not up to snuff and also because Firefox should also be able to compete. If you block browsers based on Chrome's dominance, Chrome effectively already won. What I predict would happen is that Apple starts investing heavily in WebKit to compete and Firefox would have a compelling offering there like it does on Android. Most people would stick with Safari because is is the default and they wouldn't even mostly be aware that it now may be worth switching due to say uBlock Origin. Safari would continue to serve them just fine.