I can't agree with you... I have never pepper sprayed a bear, but I work in a field requiring annual training with oleo resin units (pepper spray) and I can tell you from observing dozens of co-workers over the years, you are as likely to spray yourself as the bear in a highly charged, adrenaline spiking defensive situation... even under controlled training conditions with zero wind or nerves to deal with it often comes off badly.
In addition, I HAVE shot a dozen or so bears in defensive situations (or seemingly so at the time), usually already wounded by a client, and you do not have to kill the bear to turn it or cause it to break off the attack/charge... but most of the time the first shot did indeed ground the animal.
Long story short... I will stick with the firearm of my choice, on the rare occasions that I feel it necessary.