Why did the trolls prototyped their lusii?

Wouldn’t you want to bring your dead pet-parent back to life?

Everyone had some attachment to their Lusus, with some exceptions- Feferi’s Lusus just died and floated into the Kernelsprite accidentally, for example, and it’s likely Vriska prototyped Spidermom out of a sense of duty rather than attachment, or… Kanaya prototyped Spidermon assuming everyone wanted their Lusii back.