Here's a thought or two.
Let's say one has 10-100 'encounters' with other people per day. If you take 2x10e6 people in the US (not incl kids) that's possibly a billion encounters. And of those how many are random meetings out in the world where you have a self-defense need. IOW, if you're not a LEO or a store owner or a road rager, you can be fairly safe in predicting you'll never encounter a situation requiring a firearm solution (if you stay away from stupid people doing stupid things in stupid places, that is).
In the home, you are more likely to require a firing solution (or maybe a 'warning solution with a firearm) if your home is targeted. In that case you are likely to have a few seconds, maybe 30 to 'get armed up', take cover and begin calling 9-11.
So it makes sense if you buy this hypothetical scenario that needing to be prepared to go all Jason Bourne out there and need to be tactically "running and gunning" is so rare as to be almost non-existent, and you will have plenty of time to get ready to repel borders, the key thing is:
1. You have a gun;
2. You know how to point the little end at the bad parts of the BG's anatomy and land a few shots at close range.
Therefore, I think it's fairly safe to be somewhat causal about wearing a firearm out and about 'on the move' as it were. We do hear about them (attempted muggings, car jackings) but they're so rare that they make the news.
(Again just offering a hypothetical. You could just as easily argue the other way).