I don't think that a soft-fork will be needed for that, but the case is not that bitcoin can't keep up pace (it can get as slow as required), but that such long time-windows allow for a lot of damage to be done even if at the end the settlement is correct. I describe the issue better in this comment recurring to the "byzantine general problem" allegory (which is the exact problem bitcoin tackles), and the comment of BitSapien points to an article that describes the technical problems in detail. It's a quick read so 100% worth it.