Conventional war never "went away." Conflict is not an "either/or" proposition...you will always see one sort going on in one region with another variety (higher or lower intensity) going on someplace else. I'm not sure why this is so difficult for people to understand.

Neutralization almost never works in the long term, because it simply buys breathing space for the larger power(s) that want to smash the object of the neutralization. This is accelerated when one (or more) of the powers involved has a history of disposing of agreements when they no longer need them or feel them to be of value. In the cases it's worked, there have usually been geographic or other reasons that mitigate against occupation or other activities.