The only relevance that the UN has now is the fact that the United States recognizes it's existence. If the US were to withdraw from the UN, it would become the mockery of the world. Look at what happened to the League of Nations, the US didn't join and it was a mockery (and that happened in a time when the US wasn't the world's sole superpower).
I despise the UN.
That's why I know it will never be dissolved.