If Aemma and her family lingered - if her grandsire's death didn't come as second knowledge to them and the greens were allies, things would be different. But there's always a threat to House Targaryen, who is closer to Gods than to men.
No Dance of the Dragons | War for Succession Between Aegon & Rhaenyra Doesn't Happen
Diverges from main storyline | May be considered OOC by some