This shouldnt need an answer, steam has an offline mode, right? If its purely there only to be used when there is physically no internet connection, i would assume there would be no need for an option, it could simply check if you have activated, see no internet connection, and automatically go in offline mode, and back online mode when it finds a connection. But it gives you the Choice.
Its a choice, at least for me, i dont want steam collecting data, reguardless of what that data is. And as it stands now, with my own findings, if you go into offline mode, steam is still trying to transfer data when there is an internet connection.
Back to the OP, everyone ignores me quoting the official system req's posted on the civilization website. It states you need an internet connection the first time you Play, and the poster is having issues installing, as is stated not only in his post, but in the title of this thread.
Like I said, I think this was the heart of my problem --
It wasn't NO internet connection -- it was a rollercoaster connection that would never quite putz out.... just hang for a few minutes, then crawl -- then zoom to full speed for a few seconds, then crawl again, etc...
I'm not exaggerating when I saw that while I was having this issue -- I was literally dealing with 20 minute boot times.... until I realized just unplugging entirely cut that significantly.