Spider-Boy and Spider-Gwen were not long-term decisions.
These were spinoff titles. If they flop, the effect on
Amazing Spider-Man is minimal.
It's a different topic to talk about a new direction for
Amazing Spider-Man, especially if you're making changes to the status quo. Writers and editors will have more flexibility with changes that do not limit the next guy (IE- If the next writer decides that she's going to focus mainly on A-list villains and not going to have any guest stars,
her successor could go in a different direction.