So this is a little odd, not sure if anyone else has experienced the same?
My 4runner has always tracked decently straight but the wheel would be about 10º off when driving straight, even after getting it aligned (alignment sheet looked fine). I bought it with ~63k miles on it ~3-4 years ago, it had been in a wreck before so I was assuming the rear axle was a little off/bent. Anyways, replaced the ball joints and outer tie rods last weekend at ~78k (it isn't a DD), got it aligned, and the thing drives perfectly straight now. Because of the low mileage I didn't think the replacement was necessary but also didn't want to get stranded at the top of a mountain.
I'm thinking that there was some looseness in one of the ball joints or something? They appeared to be original. I'm pretty sure I had the same thing happen on one of my old Integras 10 years ago where i first used cheap LBJ, the thing never tracked properly, then replaced them with OEM parts a couple years later which fixed it.