I didn't mean it to come across as a douche bag thing to say, but there is a lot of truth to it. Nephrology today is not your grandfather's nephrology.
I went through the application process and the fellowship and have seen the changes first hand. Nephrology is in a state of crisis right now. Just 10 years ago a decent amount of American graduates went in to it. The number has gone down every year since then. There are more unfilled spots after the match than ever. Programs scramble to find anyone, and yes I mean anyone, as long as you don't have a history of a felony conviction, to fill a spot.
Not to sound all Donald Trump and xenophobic, but lets just be honest here and not ignore the obvious. We practice here in the United States but currently have a specialty where hardly anyone who graduates from American medical schools wants to go in to it anymore. This is not seen in any other specialty. This is not seen in psychiatry, family practice, pediatrics, PM and R and certainly not any other subspecialty in medicine for that matter. Faculty in academic settings are aware of this and are bewildered as to what to do. It is a shame, but it is the truth. It doesn't mean that foreign graduates can't be capable nephrologists, of course they can. It is just a crisis that starts in medical schools in this country that there is a specialty that no American grads want to do. Sure you may be willing to name some American grad you went to residency with who went in to nephrology, but today that is the rare exception.
I trained at a university program that no doubt would be considered a top tier place. It is as if the nephrology program is in a different world inside those hospital walls. While cardiology and GI and whoever else is taking fellows who are also trained at top tier places, the nephrology program out of desperation for going unmatched is interviewing and ranking candidates who are at the bottom of the barrel so to speak.
There is definitely a certain degree of self selection with nephrology, whether people are willing to admit it or not. It may be politically correct and cute to say that everyone who chooses nephrology does so because they love nephrons and tubules and glomeruli. Sure there are some who do. That being said, judging by the quality of applicants that I have seen and people in my program see applying, we know that many of them could not do any specialty other than nephrology. Again, everyone may have some anecdotal story of that friend from residency who was AOA and from a top 10 med school who could have done any specialty and still chose nephrology, but that is again the exception.