1) road decommissioning to be is intentionally using government money to take out a road. I am not in favor of that option becuase I hear too often the government does not have the money to upkeep the current roads.
If a road goes away becuase of a landslide, or rerouting of a river, then putting up barricades just before the problem is my recommended solution.
2) Road decommisioning means less access for all of us. For example, when the Goodell Creek road was turned into a "roadwalk" you will see less users in the Pickets. If the North Cascades National Park administration whines becuase they do not have enough funds becuase not enough people visit them, then this is one primary example of not planning for the future. More access, means more people. More people means more funding for certain parks. The more a park is used, the more money will be allocated to it. A primary example is the gate now on the Middle Fork of the Snoqualmie. My recommendation would have been to NOT put up the gate, and just let the road take its natural course. Now the gate on the Mid Fork Snoq has limited people to NOT use the trail. Nobody I have talked to will ever want to walk an additional 7 miles to get to the old trailhead.
3) see the Mid Fork Snoq example above. I will never use that trail up the Mid Fork Snoq ever--that has limited my access. Same as can be said for the road to Monte Cristo. The road is not decommissioned--it is blocked. Road decommissioning will stop me from using the wilderness as much. When I use the wilderness less, so will others. What that eventually will mean is less voices FOR future wilderness.