Why could the one ring not be wielded by Gandalf, Elrond or Galadriël to defeat Sauron easily ?
Because The One Ring corrupts those who are in its presence? And Ring itself seeks to return to its master (Hence why it calls to the Nazgul when it is worn).
It's clearly outlined when the Fellowship of the Ring is created, the reason why Frodo was tasked with carrying it (Despite many powerful people being at the creation of the Fellowship, including Gandalf) is because he, as a Hobbit (Of good nature) was resistant to the corrupting power of the Ring (Though, still susceptible, as is shown when he starts to turn on Sam late into his journey. Even Sam, with his good nature and temporary holding of the Ring starts to be corrupted when he dreams of becoming Samwise the Great).
This isn't a "Tolkien told you so" situation, but the a premise that is built upon throughout the entire story of The One Ring. Even going as far back as when the Ring was first severed from Sauron's hand, where instead of being destroyed right away, it corrupted Isildur who kept it and began to turn evil until he lost possession of it in the river where Smeagol eventually found it (And corrupted him too, turning him into Gollum)
The Rings of Power have influence over people (That is the basic premise of their title "Ring of Power"), with The One Ring having an influence that is pure evil in nature. This influence is more dangerous in the hands of people with innate power like Gandalf because of the sheer evil they can perform when they are corrupted (And being more innately magical, they are more susceptible to the power of the Ring) which is clearly evident in Saruman, who despite never being in the proximity of the Ring, becomes completely corrupted by it and does a lot of evil what with churning out Sauron's army and attempting to corrupt Gandalf.
It is never arbitrarily stated that this is a thing randomly. It's the core premise of the entire setting and thourougly explained and explored over the many works of Tolkien - From the mainstream works like The Hobbit and the Lord of the Rings trilogy, to even the Silmarillium (Which is where much of the backstory around the Middle Earth setting is found)