If your membrane is degraded from too many sweaty bush tramps then you are, indeed a bit fucked. Best bet is to not sweat :)

But otherwise, good jackets only wet out (don't beed, absorb!) once dirt (hydrophilic (likes moisture)) gets in the pores. As you said, a wash with grangers 30 deg (what arcteryx recommends and seems to work well) should sort that out. I think its best to wash it, spray it with a DWR (avoid wash ins for a few reasons) and then tumble dry.

 But yeh, wash your jacket every 10-20 days of use i think, good to get the oil out of the 1st layer and dirt out the face fabric, and shouldn't need DWR if its washed properly.