I think how you use the barrel has a lot to do with it, too. I have a friend who retired a PRS 6.5 Creed barrel this year at 4500 rounds. He was having to really scrub the barrel at the end to keep it shooting after every day of competing, but it went further than what I expected, especially considering lots of 10 & 12 shot strings.
From a hunting perspective, I think you can easily get to the 4,000ish rounds, especially if you're limiting those times where you're sending more than 5-6 round strings at a time. Letting a barrel get hot is the quickest way to kill the throat. If you're easy on the barrel, they will shoot WAY longer than most people expect.