Why would they? Embracer don't spend money on games, they get other fools to do that. You would need a lot of money to invest in a new saints row game or it will get clowned at especially with GTA 6 coming and costing billions.
Saints Row did well in the era where it was cheap to develop in, but open world games have come a long way since then. The last game looked and played like a 360 game.