That does happen though. Kid Bu blows up the planet.That doesn't matter.
Seriously, I know that this is probably the wrong website to have this opinion on; but none of that matters. It's just a sort of literal hyperbole used by an author who didn't really care about implications when he wrote it. Just abandon this idea that planet busting matters. If you go down this rabbit hole, then the Saiyan Saga is where power levels peak. Nothing matters at all after that point, because after you can blow up planets, there's just nothing to escalate to. Because you can't FIGHT someone who can do that. It doesn't matter how powerful you are if your opponent can just blow away the rock you were defending in the first place. Nothing makes sense in a world where Vegeta can blow up planets and yet we're supposed to care about the stakes. Because after that, if a fight takes place on the surface of a planet, it's because the participants have either agreed to some kind of gentleman's truce where nobody blows up any planets so they can have a punch up, or because they've forgotten they can do that for no reason.
Everything, even DBZ itself, makes so much more sense if you just ignore all planet busting feats and pretend they can't do it.
The ONLY time anybody seems to USE their ability to blow up planets properly is in Resurrection F when Freeza decides to just blow up the earth because he wasn't having fun anymore, and then they immediately retconned it in universe via time travel. Thus making it like it never happened at all. It's nonsense.
Before that everyone else either kinda liked earth,needed it, or didn't care about the planet enough to blow it up. Raditz couldn't destroy it, Vegeta needed the dragon balls, King Cold gets one shot, the androids were once humans and like earth, Cell needs a place to hold the cell games.
Then we have Kid Bu who promptly decides fuck this I'm out.