It's totally repairable back to perfection - but it's going to require a new rear quarter. Crumpling over body creases is very difficult to get right and it looks as though the whole panel has been misshapen with lots of "waviness" to it.
I had similar (arguably worse) damage to my rear quarter and it was repaired at a bodyshop without a new panel (or filler, apparently) and I honestly couldn't tell it had been repaired. It was an insurance job though, so I couldn't tell you the cost, but the car was barely a year old at the time.
Before:
After:
Hard to tell in the pictures, but I never noticed any sort of waviness in the panel - believe me, I spent a lot of time scrutinising it as the accident happened just a couple of months after buying the car