It was dangerous in the 70s and early 80s, but it was pretty easy to avoid a lot of that danger. It was the random, unexpected danger and crime that'd get you. Problem was, that random, unexpected crime wasn't really restricted to the so-called "dangerous" areas of the city. It was always best to travel in a group, or better yet, a gang. Ha. Or with your band, if you looked like a gang.
I have to say though, as shitty and sometimes difficult as it was, I preferred the city back then to what it is today, which is more or less a city for tourists and the rich. Of course I didn't have to live there, the way some on this forum did.
The same thing could be said for a lot of big cities at the time. Los Angeles was certainly dangerous in the 80s, and they wouldn't just rob you here, they'd kill you for nothing. Same with parts of Chicago, Philadelphia, DC - it was an interesting time for American cities, after their heydays, but before they were re-civilized.