Because you think it makes sense to cut down apple trees in Washington because it's cheaper to import them from China and New Zealand.
Perhaps it is, perhaps it is not. I am not privy to the business operations of the institutions that make these decisions. It may be that I would act differently, were I in a position to do so.
I do know, however, that they operate under market forces (unfortunately, federal involvement in agriculture greatly distorts true price structure). It may be that, under current price conditions for all facets of production and distribution, it is more efficient to engage in the current mode of import/export and nationwide shipping than otherwise. Were these conditions to change, production would adjust accordingly.
One must also recognize that our current cornucopia of food is the result of consumer demand. If consumers, like most of my customers, want locally-grown, seasonal produce, then that is what they will get. Currently, consumers demand nearly all foods at all times of the year. So long as there is the capacity to do so, this is what agricultural producers will meet.