The English Civil War was like a massacre for the Royalists. They were outnumbered, had less land, money, ETC. But do you think it COULD have turned out for the better? For example, at Marston Moor, Prince Rupert attacked the siegers, after stoping the siege. Do you think he should have done that or instead marched back down to aid the King? Was it possible for the King to win at all? Also, nowadays, Oliver Cromwell, second in command, is more known than General Fairfax, first in command, Ok, so Oliver won his half of the battle quicker than Fairfax, but still Fairfax was the commander.
I don't think Rupert could afford heading southwards. With the Scots in the war, all the royalist position in northern England was threatened. He had to march north. Cromwell is most known because his later political rôle. Sir Thomas Fairfax is often forgotten, even if he was the architect of the parliamentary victory at Naseby.
It's just like people to forget Fairfax and not Cromwell, they learn what they want to learn. Also, I feel sorry for Rupert's dog if he took it into battle with him...
The civil war was at times a very close run thing. The royalists inflicted several heavy defeats on parliament but never managed to gain the professionalism of what became the NMA. Yes Ruprts Spaniel did go into battle running beside Ruperts horse...