I think what will ultimately decide is after a few expansions, if EA begins to see a degree of Consumer fatigue due to cost vs benefit for Sims. When the game and all of the "stuff" and expansions get too expensive to keep up with for the average person, you'll see a sharp drop off in numbers. Kill the franchise? Nah. Don't make a Sims 5, just keep churning the Sims 4, eventually make the base game "free" on Origin and then continue to rape consumers for content and expansions. That seems like what EA would do as a contingency. Hardcore fans can continue to pay out the nose for gameplay stuff and everyone else will just move on.