I think that forgiveness is a fad, a passing fad, kind of like the mindfulness popularity. Why should I think that forgiveness will last a long time in Western culture?
Forgiveness is likely to continue because it has been discussed for thousands of years. It is sad that forgiveness has yet to be taken seriously on the societal level. By that I mean this: There never has been, from what I can find, a thorough-going discussion in any secular community on the importance of applying both justice and mercy/forgiveness together in the larger community. Justice has been paramount and forgiveness virtually ignored. So, forgiveness likely will continue to last within individual human hearts, primarily because that has been the case, as I mention above, for thousands of years. It is my hope that societies will awaken to the importance of letting justice and mercy/forgiveness be part of the dialogue of how we should interact with one another.