All bugs aren't created equal. Malware users are vastly more likely to consume existing malware than create it and malware creators have an easier time creating

All bugs aren't created equal. Malware users are vastly more likely to consume existing malware than create it and malware creators have an easier time creating code to attack known issues that have been fixed than finding unknown issues. Today's fix is a blueprint to attack people running yesterdays software. Ergo you are most likely to be attacked using exploits that are both known and fixed because you are running old unpatched software compared to new bugs in recently released software. In addition recently released browsers are great but your browser also relies on security features from your OS. I don't agree that its sufficient to run the most recently released browser on your old OS. Your up to date OS complete with new bugs is by far the best choice.