Returning projectiles returning on death.

So something I've come to notice throughout many games is returning projectiles returning upon death. Ekko, Ahri, Sivir, Lux all of their boomerang abilities return after death, often getting a kill in a close battle, or providing yet another danger to consider when trying to kill them. If this is intentional that's fine, but i'm having a problem believing that because of inconsistency. The champions previously listed all return 100% of the time after death, Where as others Such as Talon completely disappear on death. If nothing else i feel more consistency would be better for these kinds of abilities. Should all these abilities return on death, or disappear on death rewarding quick kills?