Ever since that fateful day when Goku transformed into a Super Saiyan during his fight against Frieza in the original Dragon Ball, Vegeta has perpetually been in Goku’s shadow. Because of his own stubbornness and Saiyan pride, Vegeta must overcome him his own way, a self-detrimental pattern that Vegeta adopts during Dragon Ball Super.
At the start of the series, Goku appeared to have widened the already expansive gap between him and Vegeta before the Saiyan Prince could achieve Super Saiyan 3 when Goku is chosen to be the recipient of a special ritual to unlock Super Saiyan God. Originally, it was believed that the only way that a Saiyan could possess the power of the gods was in this way. But Vegeta gains the ability to unlock this godly ki without having to partake in the ritual, transcending to Super Saiyan Blue and then Perfected Super Saiyan Blue, along with Goku.
But then Goku once again takes another step beyond Vegeta when his fight against Jiren during the Tournament of Power awakens the imperfect version of Ultra Instinct. In Vegeta’s eyes, Ultra Instinct was tarnished. He, therefore, needed to find his own way to surpass Ultra Instinct, which he accomplishes by discovering that a level beyond Perfected Super Saiyan Blue exists: Super Saiyan Blue Evolved. But Goku soon begins perfecting Ultra Instinct, which threatens to surpass Super Saiyan Blue Evolved. Originally, Vegeta attempts the unthinkable by accepting Beerus the God of Destruction’s help to learn his godly destructive power. But this ends up not being much help against their latest enemy, Granolah the Cerealian. So Vegeta once again depends on his own creativity and invents his own transformation, which takes the boundless power that Ultra Instinct provides, while keeping his mind in control of his body, unlike the original technique, and then fuses it with his own personality.
Although Vegeta’s creativity led to him inventing or discovering new transformations on his own, it might be the reason why he can catch up with but never surpass Goku, who just wants to improve what he already knows rather than trying to come up with something new. For example, Goku is currently perfecting Ultra Instinct, a state which he knows exists because the angel Whis is teaching him how to master it. Meanwhile, Vegeta ascended beyond Super Saiyan Blue with the Evolved form when he didn’t even know there was anything beyond Perfected Super Saiyan Blue. Goku only accomplishes something similar when he discovers Super Saiyan 3, but this was by accident. Goku, who was dead at the time, was just training nonstop and eventually stumbled upon the transformation, which can only be achieved in an unusual circumstance (and learning something when you’re dead is definitely not normal).
Vegeta is essentially sabotaging himself by making it so he can only get stronger creatively as opposed to naturally in Dragon Ball Super, which undoubtedly takes more time. The Saiyan Prince doesn’t just want to surpass Goku. He wants to overcome him in his own way. This adds an additional variable that Vegeta must contend with, which gets even more complicated every time Goku widens the gap between them. Meanwhile, the only obstacle in Goku’s way of getting stronger is himself. He just trains without worrying about how he’ll become more powerful. That’s why Goku will always be stronger than Vegeta unless the Saiyan Prince somehow gets even more creative. But what’s more creative than the Ultra Ego transformation, which involved Vegeta fusing his own personality into a preexisting form (Ultra Instinct) that he already manipulated into a unique version of the original? That, or he can give up on his pride. But that will never happen, will it?
