WSJ article focuses on the 'doctors' loophole':
http://www.wsj.com/articles/u-s-student-loan-program-proves-costly-1448042862?alg=y
http://www.wsj.com/articles/u-s-student-loan-program-proves-costly-1448042862?alg=y
The PSLF program is unsustainable and will most likely phase out or modified to prevent high earners from taking advantage of it. On the other hand, I highly doubt that IBR/PAYE/REPAYE will go away.
Personally, I wish the gov't do away with all these programs and reduce the interest rates to 3-4% (a fraction above inflation rate).
In most cases even with max deductions, the total of that 120 payments is equivalent to the original principal of the loan. In the grand scheme of things, it's like giving docs a interest free loan in order to practice in underserved areas.