Should also be kept in mind that we never truly know why any series ever ends.
“axe” or “cancellation” is never officially used by Jump. The fandom refers to a series ending early as an axe, but Jump will only ever say a series is “ending”.
We only have the example with Toriyama(well maybe there’s more, but Toriyama is the only one I know of), but a manga artist can just request an early ending to a series themselves if they want.
iirc there was even that interview where an editor claimed that some series are serialized with the intention of them being short(don’t quote me on this. Idr if that was exactly what was said, but if someone else remembers the interview please correct me if I’m wrong).
But point is, Jump is pretty secretive about their whole behind the scenes process. If an axe doesn’t make sense to us we should keep in mind that while it may be a genuine cancellation, there could also be a dozen other things going on behind the scenes that we’ll never know about