And there's an interesting 1967 study that set out to determine if blacks in Chicago would switch more to knives if the city banned guns, and whether their homicide rate would go up or down. They figured it would probably go down, but weren't sure. The murder rate their remains extremely high despite the ban they enacted.
Here's the reason.
ALL THEY HAD TO DO IS LEAVE THE CITY OF CHICAGO TO BUY A GUN.
Likewise, when you ponder as to why Washington, DC's murder rate has always been so high...
ALL THEY HAD TO DO WAS LEAVE THE CITY OF WASHINGTON TO BUY A GUN.
And so forth and so on. You seem to think that Chicago and Washington and really every other example you throw at us is a city surrounded by a vast no-man's land where no human or creature can exist. Sadly for you, this isn't the case.