+1 on what Heather and Wandering Daisy said: It depends on the bears in the area. It also depends on the firearm proficiency of the person; it takes a lot more training and practice than most shooters have gone through for them to rely on a firearm as a weapon, in my opinion.

I'd also add that it depends on the culture of the people in the area. I grew up in SE Alaska, where it was almost seen as irresponsible to not carry a gun for bear protection. Now I live near Seattle, where carrying a gun on the trail would probably end up in 911 calls and a lengthy discussion with a ranger. "When in Rome, blah blah blah."