> In other words, it's gonna be alright.

In the long run, sure. But in the short run, were there Irish gangs, German mafia &c.? Were those forms of criminality different from the forms prevalent amonst ethnic-English Americans of the same time period? I honestly don't know.

What sort of social upheaval and strife occurred along the way to assimilation? In the long run, things might be okay, but how much pain will there be along the way?