Regarding Vegeta's speech in the Kid Buu fight

[Spiral-Force]

Vegeta's analysis of why Goku is better than him:

Vegeta fights to win, for the fun of it, to kill enemies, and to puff up his pride. Goku fights to better himself and to push his limits.

The question is: if Vegeta used Goku's blueprint early (i.e. after their first fight), would this have made any difference to the rivalry?

If not, due you view this speech as redundant?

 

[Yoshi]

Yes it would. Vegeta is naturally more gifted than Goku so if he chose to fight like him as well as train like him, he would be just as strong as Goku if not even stronger.

 

[ahill1]

Difference as in, Vegeta being always up there in Goku's level?

If so, perhaps... It seems he saw Goku's pursuit of power being purer than his own as something that made Goku more prone to achieve bigger results in his training. Like, Goku's mentality as a martial artist, of seeing the whole game as a "funny" thing, in the sense of getting inspired to push himself harder if there were enemies stronger than him as a more conducive approach to get the best of himself.

Vegeta would get frustrated and work his ass off not to be behind, but more under an unhealthy competitive nature, as if he weren't able to live with the fact that he wasn't the best. Goku seemed more like always welcoming the thought of stronger enemies for the thrill of challenging himself, not making it simply a "I'll prove I can beat you" in a grudge way, more like a "to be the best version of myself and surpassing what may seem tough".

 

[Spiral-Force]

What caught my attention is that Vegeta ascribes behavioral traits for why Goku is that good. While earlier in the arc, Majin Vegeta described Goku as being more gifted than he is. When you think of the term gifted, you usually think of something innate. What Vegeta mentioned in the Kid Buu fight doesn't seem like something that would be unattainable, although he is quite prideful about outdoing Goku with his own methods, so you could say there'd still be a hurdle for sure.

 

[Warmmedown]

I don't think that's what Goku's motivation was, really. Post-Tao his motivation was to help Upa. His motivation after Raditz was to save the Earth. A motivation while fighting Vegeta was saving the Earth. His motivation on the way to Freeza was to bring Chazou, Yamcha and Piccolo back and also to overtake Vegeta. A motivation during the fight with Freeza was revenge for Krillin/others killed and to stop an evil person. His words to Krillin when Vegeta was defeated indicate he cared about being the strongest, as did his fights in the tournaments. He's not only looking to better himself - he's comparing himself to others, and he's looking to help others.
Post-Cell is when he wasn't motivated by others or trying to compete with anyone (unless rivals like Pikkon are canon, which they could be, even if he didn't mention them in the manga). However, here he had the benefit of being in the Other World, with less fatigue to his body. So I would put his gains as down to that. Ignoring that would be like saying the reason Goku got so strong in the rosat under Mr Popo is because of his motivation and not because of the rosat's environment.

About it being attainable or not, have Vegeta's motivations gone that way in Super? I guess he does train for fun more in Super, like when he trains with the weights alongside Goku. He's more motivated by training/fighting for others now, and he's caught up with or overtaken Goku sometimes (is it any more than in Z though? He was sometimes the strongest in Z too). So maybe it was possible to copy Goku, but I don't know about fighting/training to only better himself, because he's clearly not doing that in Super, but I also don't think that was an accurate assessment of Goku anyway.
But to answer whether emulating Goku's motivations have made him stronger in Z, I think probably, because it seems like he's had better gains in Super than in Z, relative to Goku. But based on Z only, I don't know. I would say probably yes, because there are times Vegeta fucked around due to his pride letting him down (post-18, post-Cell) and having other motivations alongside his competitive pride (which Goku also has, just less pronounced and less arrogant) could have helped him.

 

[Spiral-Force]

I'd say Vegeta's assessment works as a gist of what's mainly thought of by them. For instance, when a villain has done something unpleasant or sinister before Goku arrives to fight them, he tends to be serious and weighs up how he can use his resources and, as per Kaioken and such, ways to push further beyond baseline abilities. Fights can be fun for him depending on the situation, but not as a main thought right off the bat. Goku makes use of his talent by working hard & efficiently; the byproduct of that is winning and saving the world. It would seem this applies to Super Goku, but he comes across more careless in perceiving danger or reading the room.