When you apply the "simple publication" lifecycle to a content
item when publishing it, you are given the option to specify the
end date.  Regardless of whether you specify the end date or not,
the "Lifecycle details" page says something along the lines of

Name         Live
Description  The first phase. It lasts forever.
Start date   Saturday, July 12, 2003 9:45:00 AM EDT
End date     Thursday, January 1, 2004 10:00:00 AM EST

Clearly, if the lifecycle is scheduled to end on January 1, 2004,
it doesn't last forever by the commonly accepted definition of
"forever".