If you've ever been ice climbing over at Banks lake in the winter, you would see that there is indeed an increase in the number of 'climbers' frequenting the area, an area that used to be mainly locals is now swarming with West Siders...
As far as Omak, Okanogan, Tonasket, et al are concerned, speaking as one who grew up in the area, there are indeed very nice boulders on private land, but ALSO very nice climbs on range land. Just depends on how much of a "stranger" to them there parts you are. If you hook up with the local climbers, and have a vested interest in the area (as in not just gonna show up once and leave your gu, poo, and cliff bar wrappers) you might just find yourself invited onto that private land.