One thing not to lose sight of is that organizations like this work to purchase private land turning it into wilderness designation, are watch dogs to keep lands wilderness, and work with private land owners to gain access to wilderness lands.
However trail building turns little used areas into freeways, over population, trash, erosion, vandalism, did I say trash, and many other problems, IMO. Then we need permitting systems, more regulatory oversight, law enforcement, etc. A person could probably do the PCT without a map, compass, or GPS. The trail is well marked most of the time, and there are so many people doing it, you just follow the footsteps of those in front of you. To me that diminishes the wilderness experience.