Well Randy, you obviously have the opportunity to spend a lot of time with your bikes.
I've got a GT-NG which I got in August and it's now got 6K miles. I can only ride at weekends and during vacations but managed to put 29K miles on my last bike a Honda ST1300 during the 2 years I had it. Before that I did 20K miles in 18 months on a Honda Varadero XL1000V.
My riding takes me and my wife as far as we have chance - Varadero went east as for as Poland and west to Spain. ST1300 did 4 trips around Europe and did a week in Austria in the passes before I swapped it. (Google stelvio to see what passes are). The BMW will be on a ferry tomorrow night (Friday) as we cross the channel to St Malo and head south through France, cross the Pyrenees and carry on south to the Costa Blanca in Spain. We'll ride about 300 miles to the ferry tomorrow, 400 to Pau on saturday and about the same mileage on sunday.
Averaging 600 miles a day is quite some miles. Why would you want to do that sort of daily mileage? Is there nothing to see or stop for? You trying to break records?
I've done around a 1000 miles a day a couple of times. Landeck in Austria to home, Strasburg-home. Did it, but only out of necessity.