I realized long ago that a single "BOB" wasn't really feasible for my own needs. Not for all-around, all-weather, all-circumstances, etc.
Having been caught away from home during the '89 earthquake here (CA), held over on-duty, I decided I also needed to expand my work gear bag to include emergency food/snacks and some other things that needed to be in the trunk of my work car (not my locker). That naturally carried over to what I felt was minimally necessary in my POV's.
Then, my wife and I were stuck in a remote rural house during that really bad storm in the Pacific Northwest several years ago. Roads being closed for more than a week due to heavy snow, ice, hundreds of trees down across rural roads. Worse in areas where rocks, snow, etc came down and closed major routes. People were stuck and died.
In our area there was no power, no emergency response capabilities, freezing temps, deep snow, local generators were over-loaded and totally inadequate in number & availability, and then the local water supply lost its power (for filtration). No propane (because local power was run out there, it being a popular recreational destination during the good months ). Fortunately, I'd learned to plan for emergencies while traveling with a family many years ago, so we had some extra gear & supplies to supplement what was in the rural house.
I decided to put together a range of "modular" bags that could be broken down or combined, depending on my needs.
Nothing involving firearms or ammunition (except for the "work" bag). Limited expensive gear, knives, etc. That stuff remained with me, on my person and in my personal bags/luggage (while using my veh's for travel).
My supplemental bags vary a bit depending upon where & when (seasonally) I'm traveling, and also for how long I expect to be gone. (Safety margins factored.)
Some stay in the car, at times, but those don't have the same amount of expensive stuff I used to carry (not since I lost about $900 worth of gear out of my trunk many years ago). That gets safely & securely stowed at destinations, but remains within easy access when I'm away from the veh.
Clothing, emergency supplies (clothing/warmth, lighting/signaling, medical, reference info, shelter, repair, etc).
I look more toward geographical/seasonal influences when combining gear bags. I worry about being able to remain warm and staying energized & alert (food), regardless of whether the circumstances compel either sheltering-in-place or keeping mobile. Having safe/clean water is important, too.
I learned the importance of good ankle support and balance assistance (climbing boots and a solid staff) when foolishly doing some casual cave exploring one time. Both saved me from breaking an ankle and becoming stuck somewhere. I was otherwise ill-equipped, though. Also, nobody knew where I'd gone that day, and I wasn't prepared for some nasty insects that left a huge bite/welt which caused one forearm to swell (but which subsequent emergency treatment at a hospital determined wasn't really a problem). I was young and sometimes acted without forethought back then.
Perhaps less focus on "hard" gear and more prep work with knowledge, training and the less glamorous equipment is helpful.
FWIW, I think the firearms/protective weapons subject is a narrow subset of this general topic, but let's just say that I realize how easily equipment might be lost, stolen, damaged or otherwise rendered inoperable. Training for use with something other than a "prized, personally-owned" firearm is preferred (for me) to building a skillset and dependence on a single firearm, especially a single type/design of handgun.