Why you shouldn’t defend against a knife by attacking the attacker? Isn’t Getting close still makes it easier to grab the attacker’s arm and limit what he can do with the knife?
Unless you both come within range of the blade, and simultaneously and permanently restrict the arm, you will be cut. Probably very much. The problem is getting within range of the blade because it can still cut you in the back and side unless you also immobilize the arm.
As in any battle, your opponent has just as much influence over how things go as you do. If he’s better at it than you, or meaner than you, or faster than you, then he has a bigger voice.
The man who wins in a knife fight is the man who is cut the least and can endure the most pain.
It is not a video game, there is no reset button. If you don’t want to get cut, don’t go near the blade. Very simple. Until your opponent forces the issue. Then it’s not that simple.