That's a 'how long is a piece of string question'
It depends how its driven, who services it, what it used for etc. I know of Merc Sprinters that are scrapped at 100k because they had faults that were not cost effective to fix, and other Sprinters that have done 400k and still going. My first 2006 Vivaro has now done 300k, and still looks and sounds lovely.
I wouldn't be overly concerned at buying a 47,000 mile T6 if it was looked after in it's previous life. The problem is that most are thrashed, crashed and trashed by drivers that don't give a damn, because it's not their van.