It's exactly why when unemployment is high that immigration is needed.
Immigrants bring with them a variety of ideas and know-how from their own homeland, even if they're from a 3rd world country.
Many would then set up small scale businesses, this would also spur economic growth.
You see, in the larger picture, humans are viewed as resources.
Of course you'll get some bad apples but the benefits outweighs it.
In the end, leaders in various countries whether they want it or not will be drawn to allow immigration but its a tricky balance.
Your point may have some ground, never seen it that way however I can easilty tell that "immigrants" are not the same.
Those small scale businesses you talk about happen often when it comes of south eastern asians and far easterne asians, sometime with middle easterns while basically 99% of sub saharian africans I see are either on welfare, begging on the streets and being manpower for organized crime (selling drugs mostly).
I still believe the deciding factor is a very strong selection, you cant allow people that have no cultural or religious compatibility with the hosting country.
I dont have data about it only my observations and word of mouth but I still have find chinese people on welfare while its the norm for africans, same for jail population.
Btw social coesion is going to the trash right now, we start to see gated communities being build and asked for....I recall when I was a kid it was no big deal to leave your bike unattended outside a shop.
Regarding women, I dont count of them at all to be loyal and their people or country...actually I like that way otherwise I would not have spend the last 10 yrs banging women around Europe.
One thing I know for sure is that women always and with no exception side with the strongest.