Inactive games are eventually deleted, when a Moderator has time to run the script that deals with them. How long they remain inactive depends on how active they were (ie: duration, number of posts, number of players, etc).
Once th game is flagged for deletion it will remain for a while (during which time it can be resurrected) before it is eventually removed from the site.
Once it is removed, it's gone, with no way to recover it.
The formula covering inactivity/deletion is as follows:
The FAQs:
The game has lapsed into inactivity, and has been inactive for a number of months equal to: 2 months × (1 + (#_of_posts / 100)) (but no greater than 1 year). At this time, it is usually moved to the "Deleted" area, where it may still be resurrected by the Game Owner. If it's there for at least one month (but usually considerably longer) and is not resurrected, it may be deleted from the site.
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