Are M3 Miles like Dog Years?

I saw a thread in which the OP has a 2001 M3 with 67,000 miles.
By the standards of regular e46s, where cars with 100,000 miles seem to be the norm, that's pretty low mileage.
My Touring had just a little bit less and it seemed like it was brand new, and I couldn't find a comparable car with mileage that low.

But those commenting on the thread seemed to think that this was a pretty high mileage M3 and that it was worth around $15k.
(The car needed inspection II, rear brakes and had some undisclosed diff issues and might need a clutch in 20K)
I've seen ZHPs closing in on 100K with asking prices in that range.

What am I missing?