What year do you think will be The Sims 4 last year before its no longer being developed for? Sims 1 2000-2003 Sims 2 2004-2008 Sims 3 2009-2013 Sims 4 2014-20??
I guess I'll go with 2020. It seems like a safe bet to me. There have been subtle hints that the game will continue to get content past 2020, but I have my doubts.