Well the game Devs figured you were going to blow through your ammo because only a crazy person with an anxiety disorder would think to learn how to actually use the knife and order to avoid using the handgun until half the zombies in the Mansion were already dead.

Related: I am a crazy person with an anxiety disorder

Admittedly this is really only a problem for me in the first game, as every other game in the series, including zero, gives you more ammo than you need.

That said the first time I played the remake of Resident Evil 2, I figured that since I played the original so many times I could just go straight to hardcore. But I found that the game having limits on how much you could use the knives really fucked me in the end, as I wound up having to start over on normal, because I got my first ever Resident Evil resource based soft lock. As I did not have enough ammunition to kill the first form of Birkin.