He's also missing anopther crucial point, trying to pin an "average life" in miles on a turbo (especially older ones) is just not feasable.
Pass me the keys to any brand new turbocharged car and I bet I can break it within 5000 miles, if not sooner.
Give me the keys to a well maintained, oder car and as long as I continue to treat and maintain it then it should be fine.
The main factor in turbocharger life length is the way they are treated, maintained and driven.
A well maintained 15 year old turbo charger will run perfectly well, someihting like a focus RS that was not run in correctly and then abused for the first few years of it's life will probably not.
IMO it's clear you have never owned a turbo charged car.
Mason