Oh how I wish that would be the case. More and more these days you see successful games have longer lifespans, even if Frontier hasn't done so yet. Not that 4 years and counting is a short lifespan, but look at Sims 4...the 10th year anniversary will be this fall. Cities skylines 1 ran for what..8 years, give or take a year? Civilization 6 was receiving content over 5 years after its release - sorry those are the main other games I play so I don't have a whole bunch of other examples.This is wishful thinking, but I don’t see why planet zoo can’t be a flagship title that is supported for years. Especially if it’s about to breach cross platform.
So even though it's not likely, there has been a trend for successful games to continue on longer than in the past. And Planet Zoo has certainly been successful.