More than 1,5 years, actually. But problem is that Civ 6 is running away. Lets look at numbers.
At this time of writing, Civ V has 15,889 players, Civ VI has 37,678 players and Civ VII has 7,666. To catch up with Civ V, Civ7 must double its player numbers. To catch up with Civ VI, it has to more than quadruple its player numbers. And that is with current numbers. 8 months or 12 months later, it could be worse.

It seems unlikely that Civ VII can catch up Civ 6, Civ 5 is possible.
View attachment 745206
Blue: Civ 5, Green: Civ 6, Red: Civ 7
Gap between Civ 7 and Civ 6 is larger than gap between Civ 6 and Civ 5 after the release.
Yea yea, Civ 7 was launched simultaneously to many platforms. But Civ 6 is available now on multiple platforms.
Lets align to the release date:
View attachment 745207
Civ 7 is obviously a loser there. To stay on par with Civ5 and Civ6, Civ 7 is missing at least 1.2M owners. Are they all playing on consoles?
I assume that at that time, Steam was still relatively young and growing in popularity, and many early copies were sold by other channels.
I got old and grew tired of tinkering