quite a few patches and "Gods and kings" released next week complete with a steampunk scenario

I wondered what happened to the Russians ;)

He didn't spend ten years on it, in the course of ten years he occasionally played that one save.

http://i3.kym-cdn.com/photos/images/original/000/210/119/+_2acc5a8841f8752904d37f90a8014829.png

Assuming he played one hour, on average, a day for 10 years that equals out to 152 days of play time. Even if he only played one hour a week, that's still three weeks of play time. I think the latter is probably more correct, he probably played a lot over a period of a month or so, then took a break for a few months before coming back, then repeating the cycle over 10 years. Steam keeps track of my game time and on some of them I have logged close to that estimate, and over a shorter period of time (Fallout 3 and Europa Universalis have really stolen large chunks of my life).

It also depends upon how particular you're playing. If you're managing every city that can take a long time to play a turn.

One thing I do prefer about FreeCIV and AC is that they provide more automation for some of the stuff that wasn't as strategically interesting.

Actually said he played it on and off when he was done with his other games.
Assuming he has a job and more than 3 games, he won't be playing 1 hour per day.
So assuming 2 hours per week (on average) that turns into roughly 6 weeks of fulltime gaming.
Which is a useless statistic but it sounds way more impressive than just saying he played the game off an on during the course of ten years which is the only reason you brought up that calculation.
My very simple statement was based on his interview and the fact that if you say that somebody played a game for ten years everybody will assume he played it almost every day until his fingers bled (some poetic license).
He still put an impressive amount of time into that game, but due to so called 'journalism' it has been inflated into something much bigger. He didn't keep a supercomputer running a world simulation for a decade, he just played a game a lot during a certain period of time.