> what would send all the criminality to that province?

Nothing would "send" criminality there, over time any place joining the USA would become the USA, and by definition it would become the average of the USA (because it will be a part of the USA)

A lot of people like to think a place will become the USA in all the perceived "good" ways like higher potential salaries, lower income taxes, more freedom, etc., but they fail to realize a place will also become the USA in all the ways that make the USA so vastly different from every other developed nation (healthcare, education, violence, crime, etc.)

But the average doesn't matter if you're in a place with low crime.

Of course it does! Those higher crime areas are using up limited time and money that could be better put to use making your life better, but instead it's being used to deal with all that crime and criminals.

Your live is measurably worse because of it.