I don't play other formats very frequently so I am bias towards Vintage, but I was suprised that Smokestack didn't make the article at ALL, not even a mention. It was the second non-mox artifact I thought of, with the first being Null Rod. I felt like I steped into Bizzaro World when I read this thread and no one mentioned it either, I found that far more shocking than not seeing it in Zvi's list.
I think it might be more of a recency bias, as i dont remember smokestack even being playable until two years ago (well after Urza's Saga release date: Oct '98).
I think most of Zvi's cards had a long term presence and were mostly immediately powerful. Even Lion's Eye Diamond didn't take that long to catch on.