Goku has always been shown to be talented, don’t forget he was born with an extremely low power level compared to Vegeta. I’m confused when I read people state Goku didn’t have to train hard when he busted his ass in training both in Dragon Ball and Z. Raditz is an example of Goku lowest potential which is why Vegeta technically beat him in the Sayain saga. If Krillin, Gohan AND Yajirobe hadn’t helped him, Goku would have died. Initially Vegeta was stronger because of Vegeta’s “natural” talent. Low class warrior vs the elite. Even after Goku trained he was still weaker than Vegeta.
But Goku trained afterwards. HARD. 100 times gravity? That’s insane. All of Goku’s training from childhood to adulthood was always on level HARD. From delivering milk by foot ON time to dozens of houses, being trained by gods, to defeating space tyrants, Goku has always aimed to push past his limit. He worked very hard.
The major difference between Goku and Vegeta is ego and that factor alone is why Goku has always became the best. All of Goku’s best techniques were taught to him. He was trained by several people. He had friends who supported him and trained with him. Goku loves fighting but he’s not above getting help.
Vegeta on the other hand is or was extremely arrogant and egotistical. He refused to train with his son and initially refused any sort of help when facing an enemy who was clearly out of his league. He gets in his own way. Whenever he reaches a new limit he becomes overly confident and goes to major extremes to proves himself.
Example: Goading Frieza to transform. Allowing Cell to reach his perfect form instead of killing him off the bat just to prove his strength. Knocking out Goku to face Majin Buu alone instead of listening when he was told Majin Buu was more powerful than they both could have imagined. Initially refusing to fuse with Goku because his ego was bruised from discovering Goku held back his power during their fight, where Goku held back BECAUSE he knew Vegeta wouldn’t have been able to handle it due to his EGO.