Smart people can be pretty ignorant about specific things that seem like common sense if its something they just don't have a lot of experience with.
It depends, they have some sprays that can reach out a little further, and they say pick a brand that can fire for at least seven seconds continuously. I thought it was pretty obvious that no one is going to walk around with either bear spray or a pistol drawn at all times, be serious. The idea is that the moment you see a bear you draw rather than wait to determine the bear's intentions. A bear charge is very fast, but there's often a bit of time to drawn upon first siting a bear. If there's no time the response depends upon the type of bear, but I believe grizzly you are supposed to make yourself small, and either fire the spray behind you while balled up or shoot from retention. That's assuming you're the target, as you may be a responder assisting someone that is being attacked in your group.
You're watching too many Hollywood movies, as no one outside of the movies carries around a Desert Eagle, lmao! Not only are they too big to hold and carry, but if you touch the floating magazine on the bottom its going to jam after the first shot! I'm not that big and can handle a Glock 20 without issue, and they are used to take down large game. If you want to carry a rifle that's fine, but I believe the statistics show that pistols are more effective in stopping bear attacks than rifles, likely because they are so much faster to draw and fire rapidly. Rifles have greater effective range, but no one should be shooting a bear with a scope and still having the right to call it self-defense.