DBZ

[The Unintelligible]

I actually lol'd

edit: I actually put some thought in it and figured why Krillin or any of the other Z Fighters never did it - they were all pure of heart that wanted nothing but peace on earth and tranquility. Power in the long run can really mess with your head.

Secondly, wishing that the Dragon Balls cease to exist could be a problem with Shenron; not sure he'd approve of it.

Third, your wish technically was already pursued by the likes of Frieza, Vegeta, etc. Immortality/infinite power.