What has either side accomplished in all these decades coveting the other's slice of Kashmir ?
I'd be over the moon happy for everyone in the region if the LOC is accepted as an IB but unfortunately most Pakistanis, at least the ones here vehemently oppose any such solution. Not many politicians here would publicly dare speak, the opposition would have come at them all guns blazing. There is, however, a window now open on India's side to get it done because there is no real opposition to Modi, all that remains of the once mighty congress lies in a heap of rubbish.
If I try to understand a common Pakistani perspective on Kashmir, here it is.
Pakistan was created out of British India as a muslim majority area. Pakistanis feel that all muslim majority areas of British India should belong to Pakistan by that principle (at least the ones which share boundary with Pakistan). If they agree on such a muslim area to remain with India, then the entire basis of formation and continuation of Pakistan as a separate identity from India is questioned.
Thus, accepting the status quo (LOC to IB) is a form of acceptance of defeat for Pakistan. It will hurt their pride. They would much rather want to die than accept the defeat. Although they know that they will never win, they still want to keep the hope alive of win one day.
Understanding this, I feel no Pakistani leader can ever afford to accept LOC as IB without some other concessions from India. If Pakistan ever becomes so weak that they are forced to accept LOC as IB, it will only lead to a temporary peace. As soon as it gets some power, it will work to renege that agreement. It is similar to how Germany was forced to accept Versalles treaty after WW1, but broke that treaty within 20 years after gaining power.
Thus, from Indian side, there are only 2 long term solutions.
1. Give up atleast the Kashmir valley to be independent or merger with Pak Kashmir. This is not acceptable to Indians, so it is unlikely.
2. Change Kashmir's demographic to make it non-Muslim majority over time, so that Pakistan loses all hope and accepts fait-accompli. I think this will happen eventually but will take several decades, as India will not want to use violence or force to achieve this change. However, this process will lead to a lot of violence as any such change will be vehemently opposed by Pakistan sponsored groups in Kashmir.