"Welp, Bear Spray is 55$ at REI. Most handguns are 500$+. You would have to make at least 10 trips where you wouldn't be able to take your Bear Spray to make up for most guns."
There are a couple of fundamental differences here... Gun can be reloaded, and afaik, bear spray cans cannot. Bear spray- 1 time use, $55, serves only one real purpose. Firearm, lasts indefinitely, easy and cheap to reload, and serves multiple uses (+1 for multiple use gear :D). Self defense, a good recreational activity, *could* feed you if needed, can also signal for help (I've seen and heard in several places that three evenly timed discharges is used as a distress signal), etc...
Also - how much practice do you have drawing and deploying your bear spray? All responsible firearms owners that carry for whatever reason, practice, practice, and practice. When seconds count, that all that could separate life and death.
edit- and to the argument about marksmanship, if you did note in that youtube video, that hunter only shot into the water. The bang was enough to make the bear reconsider its actions. Dunno how reliable that is though...