Yeah except the flaw of the paper you posted ended its analysis with the immigrants themselves.
What happens by the 1st gen? 2nd gen? 3rd gen?
Hey, here's another anecdote for you: my father-in-law immigrated to the UK in his 20s not speaking a lick of English and with the equivalent of 100 pounds in his pocket. Eventually immigrated to the U.S. Used his mechanic skills that he learned as a conscript in the Yom Kippur War tank maintainer to get a job fixing cars. Eventually got a job working for NYC utilities. He's now retired and has a pension that is just shy of 6 figures, an apartment in the upper East Side, and 3 kids with multiple grand children. Had to deal with racist stuff like the FBI questioning him about 9/11, but that still didn't deter him. Why? Because he was tattooed with a cross as a child, and if he had stayed inside his native country he would have been burned at a cross by now. That's real oppression, not some idiot cop asking stupid questions.
By the way, he still can't read English.
The point isn't that it's easy. The point is that it can be done with hard work and personal accountability. Measure success by the generational gains made, not by comparison to established wealth.