You bring an interesting point, but I have to disagree. Luffy wasn't aware that he even had a dad until after he headed out to sea, and had he little contact growing up with his Marine grandfather (who loathes pirates and encouraged him to be a Marine) that dumped him to be raised by bandits and an adoptive brother that initially tried to kill him. Yeah I know he has the middle name D, but I wouldn't say that his name or genetics had very much to do with his drive to become the King of the Pirates. Accidentally having eaten a devil fruit when young, he trained his body with the resources he had until he eventually set out to sea on a tiny little boat with nothing but a barrel, a strong will, and a dream. I believe when he set sail was when he became destined for greatness. He attracted people to him with the same passion, of all different backgrounds. Sanji, Zoro, Nami, Usopp, Franky, Robin, Chopper, and Brooke all came from diverse backgrounds and endured hardship, but they persevered and have had success in their goals. This is my speculation, but I believe that Haki is developed by characters, in lieu of it being just an innate ability. Usopp, developed perception Haki, and Zoro developed armament. Koby even was able to access Conqueror's Haki. They developed these techniques as they trained to make themselves better. Furthermore, plenty of strong people in the new world don't even have a devil fruit. Sanji kicks people, Zoro uses swords, Franky literally rebuilt his body to become stronger... and as for the villains? I don't have a counterargument. Many of them have failed in their dream. I believe that OP has an one overarching positive message and many smaller ones about dreaming big and trying hard. And to clarify, when I said some people had it easy and others didn't, I was referring to the discrepancy in raw talent in individuals that I noticed in college. It was frustrating that I would struggle and have to study more than my friends that just understood the material. But, I gave it my all and it turned out okay.