I would agree that there are many measures of personal defense that are useful. All of them require many hours of training to become truly useful.
There is a truism though, that a firearm puts a potential victim on a stronger footing than a stronger attacker, training notwithstanding.
As it was said: "God made man, but Sam Colt made them equal."
There is a truism though, that a firearm puts a potential victim on a stronger footing than a stronger attacker, training notwithstanding. The attacker already has the advantage of choosing the time, place, and method of attack, as well as picking out the victim. As a defender, you start out in a very deep hole. You need something not only to equal the odds, but slant them significantly in your behavior.
When your opening defense succeeds, you and your attacker both have to choose to flee, or have at it again. It's this follow-on that I feel people need to give more thought to.