When your game engine's license can bankrupt you just because some game platform owner like Epic decides to put your game on as the freebie-of-the-week, so that

When your game engine's license can bankrupt you just because some game platform owner like Epic decides to put your game on as the freebie-of-the-week, so that you now owe several million installs times 20 cents, you take Unreal over Unity even if it costs more (or you start looking into Godot or the like). This is how you kill a product.