First off, I never said Pakistan would or should copy Japan's method, that would be terrible idea, all I'm talking about are results.
Next, population is a major issue. India has to cope with over a billion people, Pakistan only has to deal with a sixth of that. If both nations grow at the same pace, Pakistan will have an easier time, simply due to a lower birth rate. Pakistan also has a somewhat centralized system, where as India leaves a lot of economic policies to individual states.
Anyway, it's a huge topic, one that I'm not suited to discuss. I only know the very basics, so I can't elaborate any further. The main thing is tax collection, which has become a major issue in Pakistan. The next government (if not this) will guarantee increase the tax base and increase domestic revenue streams