Well Nawaz made those agreements when he and Ishaq dar were maintaining a constant dollar to PKR rate at 100. It was a good deal then. The country was growing at decent rate of over 5%. And had it continued this payment would have been easy. So what started this meltdown? Imran's constant dharnas and labbaik sit in, which undid the growth. Contrary to popular belief here, terrorist attacks and US drone attacks came down in PML-N period not Imran's. Army too wanted PML-N out for their own reasons. So growth came to a naught, these expenses became a huge overhead. All of PML-N financial plans came to tatters and Pakistan as a country had to stare at a massive debt blackhole.
So moral of the story is to let any government in power to do its job till the end and make a decision on their performance. Too many institutions of Pakistan have a stake in administration and each vying to undercut others. I don't know if it is cultural but it has become a bane for Pakistan for too long now. Pakistanis should come together and should make sure that boundaries are established between various organs clearly.