They haven't integrated and they never will. There were leaks showing Amazon's union busting efforts for Whole Foods - the more diverse a city, the less likely locations there were to unionize.
Common sense was that Ocitanians and Bretons could never integrate into France.
Common sense was that hundreds of independent principalities with mutually unintelligible languages could never integrate into Germany and Italy.
Common sense was that Samnium and Lucanium could never integrate into Rome.
Except all of them did and those countries were stronger for it.