The deaths of the "Three Sons of York" were "ironic" to their characters
1. George was a lover of power and did have the means to have it but he was quite an impatient person, instead of getting more power, he was drowned in wine like a fool.
2. Edward IV was a super warrior, undefeated and full of strength. His enemies grew to fear him on the battlefield to the extend that any uprisings against him was already known to be a failure leading Jasper and Henry Tudor to simply to "wait it out" in Brittany. In the end, instead of dying on the battlefield or growing old with his beloved children, he died weak of pneumonia.
3. Richard III felt himself to be the most "honourable", just like Edward IV, he loves to fight on the fight on the field on battle. His greatest weakness was his inability to see the dishonour around him. His total victory was snatched away due to the dishonourable actions of one lord.
The Three Sons of York alongside Lord Warwick "The Kingmaker" could have easily stabilised and rule England and maybe soon enough conquer Scotland and then France.