This is not a troll. Just really curious.

The premise of this thread is dependent on the inverse of the statistic you give above.
We know exactly how many bitcoins currently exist. Does anyone regularly calculate how many bitcoins DIDN'T trade over any given period of time. I'm sure may of your $1 million coins traded hands multiple times.

Someone crawled the transaction graph a while back and found that a huge number of coins had never traded EVER. They still sat in exactly the same outpoint they were "mined" into. I guess the question is, does anyone graph the total coin age of the system?

They might. I've been gone a while. It's not fool proof. People often move their coins from one personal address/outpoint to another. But it would show what percentage of the coin base is in cold storage.