I probably would not use OC in my house.
1) I may have to move. I can't do that nearly as well if the hallway is full of OC. I don't own a gas mask.
2) If I can't immediately find my wife and children and make sure they're safe, I'm going to move towards the intruder and be ready to neutralize any threat. OC spray isn't usually the best choice for this.
3) OC spray isn't as effective as firearms are in trained hands. In a home invasion, I'm not beholden to a police officer's continuum of force, I'm not trying to deter a low-grade threat, and I'm not in a non-permissive environment. There is no reason for me to not use the most effective tools at my disposal.
I used to share your philosophy, but I have reconsidered. IMO, the only way a firearm is a deterrent is if it is immediately available day or night. If it is locked up, could you get it in time? I couldn't figure a way to turn on a light, find my glasses, open my gunsafe, and deploy a weapon in the 15 seconds it would take someone to break out my bedroom window and jump in.
Back then, my solution was to hide a pistol in my nightstand, or lean a shotgun behind the door.
But:
Am I going to remember to lock it up every time I leave for milk and eggs?...No
What if the intruder was in the house when I or my wife came home, and had found the gun?
What if the unexpected footsteps in the hall was not a burglar, but a family member? (Do your adult kids have access to a house key?)
If the intruder is already armed, he would have the jump on me. If not, I don't want to arm him.
My solution:
A light-sleeping house dog with a ferocious bark, a large can of Sabre OC Red and a tactical light in each nightstand, with a followup welcome with a weighted billy (all of which I am thoroughly trained to use).
If I accidently mace my practical-joker son who comes home on leave from the Air Force unexpectedly, or my daughter who comes home from college without calling, we get a do-over. With the gun, we don't.
Don't get me wrong, I am an NRA member, and Second Amendment supporter. I just can't figure out a safe way to protect my house from intrusion with my guns.