The following contains spoilers for Dragon Ball Super's "Granolah the Survivor" arc by Akira Toriyama, Toyotarou, Brandon Bovia and Caleb Cook, now available in English through Viz Media.
Dragon Ball Super's “Granolah the Survivor” Saga featured multiple titanic battles for both Goku and Vegeta. The first clashes came with their enemy-turned-ally Granolah, then they all teamed up to face the dastardly Heeter family's primary muscle, Gas.
Vegeta fared quite well against both Granolah and Gas for a while, even revealing his impressive new Ultra Ego form for the first time against the former. While the Saiyan Prince did, as usual, have a crucial role to play in this arc's final outcome, he once again did not get the pleasure of destroying a major villain himself. Many fans would wish on the Dragon Balls for Vegeta to decide an arc's final battle just once – but it's unlikely to ever happen.
Vegeta Has a Specific Role as Dragon Ball Super's Deuteragonist
By definition, a deuteragonist is the second most important character to a story. They are there to help drive the plot progression and aid the main character's development. It could be argued that Gohan was Dragon Ball Z's deuteragonist at times – particularly through the overarching “Cell” Saga – but Vegeta unquestionably fills that role in Super.
Though he's gained new perspectives and values in life since settling down (as much as a Saiyan can “settle”) with his family, the focus and goal of Vegeta's training remains to be the strongest warrior in the universe and surpass Goku. While he's continued to successfully ascend into many of the same forms Goku has – from classic Super Saiyan in DBZ to Super Saiyan God and Super Saiyan Blue more recently – the final battles from nearly every arc see him aid the protagonist's efforts rather than taking the villain down himself.
Vegeta's Primary Purpose in Dragon Ball Super Is to Push Goku
Ever since Dragon Ball Z's “Cell Games” Saga, Vegeta has played a critical part in the defeat of nearly every major mainline villain. His last-ditch energy blast distracted Cell just enough to allow Gohan to finish him off. Years later, he valiantly took a brutal beating from Kid Buu to give Goku time to power up his Spirit Bomb.
Even in the excellent Resurrection F film -- where many fans believed Vegeta would finally get to exact personal revenge on Frieza for destroying most of the Saiyan race -- the plot teased this very outcome but then took it away and gave it to Goku once again. Against Zamasu and Goku Black, Vegeta's and Goku's best effort was to fuse together, and even then they needed the Grand Zeno's help in the end. Vegeta put up strong individual performances against both Moro and Gas, but yet again, he got his eventual beatdowns as the story paved its way for Goku to get the final spotlight.
Unless Goku dies and is incapable of being revived or Vegeta gets his own side arc at some point, it's unlikely the Saiyan Prince will ever kill off a major villain in Dragon Ball Super. Their interplay is constantly entertaining and they push each other to greater heights, but Goku will probably always get the final say in major arcs simply because he's the protagonist. In the end, Vegeta's greatest opponents are the ones he'll never overcome: Akira Toriyama and Toyotarou.