Why Goku was almost always stronger than Vegeta and why Vegeta is ahead now

I'm sure many of you already know this but I want to say it anyway. It's not that Goku is an inherently better fighter (you can argue that Vegeta actually is). It's Goku willingness to train and learn from others that makes him stronger. Throughout the Dragon Ball series Goku has had numerous teachers which include Son Gohan, Roshi, Karin, Popo, Kami, the Yardrats, Kaio, and Whis. Most of the techniques he uses today such as the Genki Dama, Kamehameha, sensing ki, Kaio-ken, and Instant Transmission are a result of his student-like approach to martial arts.

Even during the last tournament, while Vegeta was fighting Hit, Goku was asking around trying to understand Hit's ability (something Vegeta would never do). Because of his unwillingness to learn from others, even if Vegeta had went last, he would have still lost. I think this is because he believes he has nothing to learn from those he perceives as weaker than him. He also has this weird belief that he has to do everything himself. A belief that has rarely benefited him.

Goku also trains a lot smarter than Vegeta. I believe Vegeta has the tendency to overtrain which causes diminishing returns. For example, despite using the Room of Spirit and Time longer than Goku, Vegeta was still not able to match Perfect Cell the way Goku did. Goku also included Gohan in his training (even if it hindered him) which helped a lot (something Vegeta didn't do with Trunks)

The reason Vegeta is ahead now is that he actually, for the first time in the Dragon Ball series, took the intiative to learn from another person (Whis). This is likely because Whis is the trainer of someone who is far more powerful than Vegeta is but nonetheless, it is part of the reason why he is stronger than Goku now.