Recognizing this is a knife forum, the OP's question certainly has a place. The anecdotes and DOJ stats are real enough - sometimes a knife is all you have, and can be used for self defense.
IN THE COMPLETE SPECTRUM OF SELF DEFENSE, it's just an option with it's own limitations, and commonly arrived at because of societal limitations. It certainly is not the best overall choice, regardless of our enthusiasm.
Don't limit your choices because of the narrow subject and it's incomplete offering - that would be like going to a really cheap whorehouse to shop for a wife. You shouldn't be surprised that the selection is less than optimal. There's no holier than thou attitude involved recognizing some tools available for self defense have superior attributes, and that some don't.
Again, in the big picture, standoff and reach are primary. That's being recognized by those who recommend blades over 4". More often in bar fights, pool cues, stools, chairs, and other objects are chosen for weapons because they can strike further than any folding knife, regardless of construction and price. And the DOJ stats back that up by placing knives third in frequency of use - after the category of "ANYTHING else."
The average America without a gun more often chooses not to use a knife - insert your explanation here. I don't know why, but there it is.
Personally, I'd like to see what Strider made in the genre of "gladius." I doubt any small gang of thugs would face up to a fight with one man armed with an 18" short sword. I expect they'd either leave or pull a gun - a demonstration of standoff or reach.
It's a fundamental law of conflict, and folding knives are on the short end of the stick.
