I have found over the past few years cars seem to be having more and more kms on it, in both the USA and here in Australia
In Australia we have HLE's (Which are all privately owned), these locations have the oldest cars and really don't care.
I have had cars in Australia from the HLE's with around 30,000-40,000 miles on it (of course displayed in KM's down here)
I made a complaint and spoke to the complaints department, the first person didn't care and pretty much said bad luck. Another person I spoke to said avoid renting from HLE's if you want new cars.
After three high mileage rentals from the HLE I now rent from the airport here, and get cars with only a few hundred miles on it and always get upgraded. Unfortunately this means paying a bit extra for the airport surcharge but I get better service and my car is waiting with my name on the board. The HLE doesn't have a board.