tiredcarebears,
I often pondered the same thing... My cat had run out of our front door so fast when I was about 12 years old.... None of us even realized she was gone till later that night. I hoped and prayed every night that she would come back to me 'cause she was my little angel, and even then I was worried because she was an indoor cat and de-clawed. She had no defenses out there with all the coyotes and busy roads nearby...
Well, about a month later, and after many nightmares of the squeals I heard in the night... I was doing dishes and looked out our back window and there was my little Sandy, jumping over our fence, back into our yard.
She was oh so happy to be able to come back in, and we fed her and I held her for hours.
So yes, Cats do come back! Just hope for the best, and know that your cat knows it's way back!
Good Luck!
-Jen