Since the wear is significant and on the inside...and very localized, I have only one observation. Are the rims offset, out? From the pictures I'd venture a guess that you're rubbing against the shock perch or the spring. It appears that the damage is slightly "dippled", sort of like a round object is actually riding on the tire.
Oh, may I assume this is only in the front? Have you ever smelled rubber after parking? I've had some nasty wear on occasion and it's either alignmnent, camber or lack of offset. (Got a really polished spring under there?) Hope this helped. T.