system
Given the following post, respond as if you're commenting on Reddit:
human
[Dragon Ball] Could Vegeta have used the Dragon Balls to wish back the Saiyan race? If so, why didn't he?

I'm pretty sure Porunga could have wished saiyans back to life.  So, why didn't Vegeta do that?  Does he just not give a shit about his people?  Or, is there some reason why he wouldn't be able to use the Dragon Balls in this way?
gpt
I believe it has something to do with how long they had been dead before he learned of the dragon balls, and that's assuming it's something he would have wanted in the first place. In fusion reborn, part of hell is shown to be a place where souls are ' cleaned' (so as to be reused, one might infer, implying reincarnation). It is possible the souls of the entire saiyan race are now inhabiting other bodies. 

Given that in DBS, the super dragon balls are used to create a new earth that was long destroyed in another universe, it is possible that they have the capability to restore the saiyans. However, by that point, Vegeta has a family and a life on earth, and may no longer even think of the saiyans. He was selfish before, now he may not even identify with the group he could revive. He could also see them as a potential threat, or even unworthy of redemption because they failed to save themselves.

If it is something that was within the power of the dragon to do, he never cared enough to ask it to do so.