Ah yes, the Silmarillion... haven't read that in a while...
I always consided the Valar (Melkor & Manwe) to be like Arch-Angels and the Maiar (Sauron, Sauruman, & Gandalf) to be angels...
Manwe was the leader of the Eagles, they rarely did anything without his approval. The two exceptions being saving Gandalf, Bilbo, and 13 dwarves from the orcs and goblins in the Misty Mountains and the rescue of Gandalf from Sauruman's Tower at Orthanc.
As for the question, it was not Gandalf's place to solve their problems, but to inspire them to fight the enemy.
He was more of a helpful cheerleader than anything else. He was only supposed to fight those things that the mortal races could not fight. IE the Balrog and the Ring Wraiths (which is why he was so pissed when a little hobbit dragged him away from the walls to save Farimir from his father)
I loved how Tolkien tied in the Hobbit with LotR saying that Gandalf helped Thorin's expidition to remove one of Sauron's biggest allies (Smaug) for the war that Gandalf knew was coming since the Great Woods fell and became Mirkwood....