I think the comments are all too pithy. Yes, it's hard to imagine being able to triumph in street hand-to-hand when you are older and/or infirm. But even when you are young and in shape, the only way to ensure you can have a good chance of winning a fight is to fight. And fight often. On the streets, in the ring, or some form of training.
I grew up in the streets of NY and I mean the streets. Lots of fighting, and I more often than not got my butt kicked. I wasn't looking for a fight, and I wasn't a pure street guy (though I may have engaged in a bit of street mahem). But the ones who typically won a fight were always fighting. I could run, had quick hands, played sports and was wiry strong but it was no match for someone who could suss out a good time to hit hard, when to move, and when to run. Because they did it all the time. Trust me, I hung with 'em or fought against them.
So if there is any implied, 'back in the day', having really been in it back in the day, I suspect there wasn't really a time when many of us could safely go it alone. As a result though, I'm not very concerned walking the streets. I have some built-in radar and attitude from my youth that really helps.
B
P.S. One of the few memorable stories about my father was when I was quite young, came home beat up, bleeding and such. He flew in to a rage, cleaned me up and then looked down at me an said, 'Tell me one thing. Did ya' hurt 'em?'.