The USFS has made it Foot or Animal. A horse can cover 3x the ground in a day that a hiker can. So if people want to make a 15 mile loop over a pass and by some alpine lakes, an outfitter can take them on a horsey ride. Costs around $200. For hunters, the outfitters will setup a drop camp, dump you off and haul out your game for about $1200/person. You can be 10+ miles in this way. Since few people own pack animals, suddenly the easy access to wilderness is via the outfitter. As I said, the USFS has made Wilderness the playground of the outfitters.

And you think bikes cause erosion..