Three chains in 10,000kms sounds like rather a lot of wear to me, or rather a short life
Have you been a bit too conservative? Did you measure the elongation?
I've done just on 14,000kms on my Rohloff in two years. The hub has had two oil changes and I will do a third in a few weeks, before we head over to Europe for a big tour. When I built up the bike I bought the chains from Wiggle. The KMC X8 chains cost me just $11 each, so I bought three and decided to run them in rotation. I ran each one for about 3000kms each then swapped them off. The first chain I used has now done 6000kms in total and is past 1/8" elongation so it's cactus. I need to bin it and swap the chainring and sprocket around, then I will put on one of the other two chains.
By the time these two are both worn out I reckon I will have done 20,000kms at which point it will be time to completely replace the drivetrain. I reckon 20,000kms is pretty good life for the chainring/sprocket and three chains.
Once this has happened I will be fitting the new Surly SS ring and fitting the Hebie Chainglider to get even better chain life and hopefully reduced wear of the drivetrain.