I assume Ubi has statistics that show how many people played the game for X hours and then didn't finish it because they got tired/burned out on it.
Better to spend the time making an amazing 50 hour game that people like from start to finish then a good 150 hour game that 2/3's never complete.
There is the wrong belief that everyone must always be bigger. Sometimes more is less, as shown by all the massive open worlds that are mostly empty or just copy pastes.