Put in a national context, New York, with a population of 8 million, will likely record fewer murders than much smaller cities. Chicago, Illinois, a city of 2.7 million people, has had particular gun crime problems this year with 462 murders so far. That would be a new record for murders in New York City, certainly in modern times. You’d have to go back to the 1960s to see murders below 400 in New York City, but back then the records were not kept as reliably as they are now
This is a great thing to speculate on, or at least far better than the alternative. In a country where violence towards one another can seem a very frequent, everyday occurrence, we should absolutely want to see more peace and cooperation among the citizens, and particularly, we should definitely want the murder rate decreasing.
The number of murders in the USA has been falling for decades, though there are variations from year to year. There are also variations between cities and states. For instance in 2016, murders in New York City are down so far, but in Chicago and Orlando they are up. Overall, however the long-term trend is down.
No, the number of murders is not decreasing in the US because so many major cities see their murder rates skyrocketing. There are too many guns in the hands of the American people, and if we look at cities like Chicago, New York, and Philadelphia, the murder rates only appear to be going up.