I am not surprised. IPL features the best players from all the major countries (obviously, with the exception of Pakistan). PSL on the other hand mostly features the Pakistani players, with a smattering of some of the second tier players from other countries. The superstars are not there, and therefore the interest from the fans will be quite low. You need players such as Virat Kohli, Steve Smith, Pat Cummins, Ben Stokes, Stuart Broad, David Warner, Chris Gayle, Mitchell Santner, Faf du Plessis.etc to attract the fans.