Exactly...and his goal is directly related to strength and being the No. 1 Swordman . so Zoro having that kind of Haki once he arrives at the top makes somehow sense.
While this is true....the people he is talking about are likely OGs who spend who knows how many years at sea. Luffy being the only one of that Generation to have it so far shows how rare it is and he is an exception...once Oda starts to giving it away like Candy it will lose a lot of impact. I also dont need why other Strawhats would need it or what it would accomplish... no once of Whitebeard Commanders seem to have it with Ace being an exception, same for Shanks etc. Seems to be more like a leader/Captain type of Aura.
I've seen people talk about even CoA and CoO losing its impact if Zoro and Sanji had it after the time skip. Especially since Luffy's training was dedicated entirely to learning it, the common thought even before Fishman Island was that they would learn Haki later as to not take away the uniqueness from Luffy. Even if/when all 3 have it, we know Luffy's special is CoC, Zoro's is CoA and Sanji's is CoO. They will all develop in different ways.
I have no idea what it would accomplish if other members had it but I'm sure they will get it. I don't know what it accomplishes now other than getting rid of fodder and making the rest of the world go wow. Usopp lying about using CoC and then developing CoO within the same arc is all I need to know that he'll be using it by the series end. Now because he is physically weak, its doubtful he will be knocking out 50,000 enemies with a single thought. It's rare but even Rayliegh said that many people who've made a name for themselves posesses it and Usopp will have one of the biggest names ever.
You can't bring up White Beard being the only CoC user in his crew and then say Ace doesn't count. Shanks I give you but we don't know anything significant about his crew or any remaining Emperor for that matter.
Zoro will parallel Rayleigh and Sanji will always be right there with him as a rival. Every member on the Straw Hat crew has shown some sort of leadership qualities with Zoro and Sanji being the ones who take the reigns when it's necessary. If we find out that Scopper Gaban(Bronze) ends up being another one of Roger's CoC users then thats all the foreshadowing I will need for both Zoro and Sanji.
Still in 10 years if I'm wrong, book mark this and throw it in my face later.