Rear Brake Pads wore down to METAL in 24k miles!

[ps2cho]

I was shocked today to brake and at low speeds the entire rear end vibrated.

I checked the rear brake pads today and one side the disk is SCORED from metal on metal, and the other side is 95% to metal.
I replaced these on my Excel document @ 140k. I have 164k now.

How in the heck does a set of REAR brake pads wear down to zero in 24k miles? My last set was put on at 75k...so they lasted 65k (and I remember they still had some life left on them maybe 5-10k more), but this set lasts 24k?
They were Textar pads.

Any ideas? If it were ONE side I would think bad caliper, but both rear corners are gone.

I also replaced the fronts at 140k as well and there are tons of pad life left (I checked that last week because I was searching for a sticky caliper for my steering pull to the right).