Why did Vegeta never reach Super Saiyajin 3? Further details:


Gohan also did not reach it.
Goku was able to do it for a short time once, and later a long time.
Gotenks did it but for a short time.
There are actually a lot of ideas about that, and one is that Goku spent a long time training in the heavens, where power is limitless and that is said to have greatly strengthened him. Vegeta on the other hand, never had that chance. As a note, Vegeta did reach Super Saiyajin 4 after gaining power from one of Bulma's machines, then he fused with Goku to beat the One-Star Dragon.