Goku is quite literally the Jesus of the franchise, that's why everyone depends on him.
Yeah and I honestly really don't like that, it's a very common trap that a lot of Shonen series fall into and it's also why Naruto is also very much despised by its detractors, other than Sasuke being one of the most badly written characters in history, the Lead Character is the Center of the Universe.
The only time this didn't happen in DBZ was in the previously mentioned Cell Saga and first 2 Sayian Sagas, with Piccolo finishing off Raditz and Goku only barely winning at the skin of his teeth thanks to Gohan going Oozaru and Yajirobe actually doing something for once and slicing off Vegeta's tail. Otherwise Goku, and in a lot of bland Shonens the Lead Character, has to do [tornado fang]ing everything because the not Lead Characters can't dare to steal the Spotlight from the Lead Character or else the Lead Character can't be the most awesomest person in the Universe.
Nothing happens without the Lead Character, only the Lead Character can beat the Big Bad and most of their hench men. Lead Character this, Lead Character that, Lead Character, Lead Character, Lead [tornado fang]ing Character all day erry day.
It's really infuriating that all of the other characters are either supports or loads, it's almost like they might as well not be there because 90% of the time they don't do anything major, most of the time they stall or they try and fail miserably and nothing changes. It really diminishs how awesome DBZ is because Goku is usually used as a plot device to wrap everything up and do most of the work.
It's why I prefer Yu Yu Hakusho much more, it's why I absolutely adore Jojo's Bizzare Adventure so [tornado fang]ing much, it's not all about the Lead Character, the other characters actually provide meaningful support and actually do things meaningful and significant!
I mean DBZ is a fun ride, and I still like it very much, but otherwise a lot of it makes me cringe with how much they kiss up to Goku and how they really trivialize the growth of other characters, even and especially Vegeta. I mean Vegeta tries to do things, but in the end it almost always falls flat and Goku has to save the day and get all the credit.