Nitpick: Istari is plural, the singular is Istar.
More general points:
People tend to forget, or not be aware, that Tolkien was a lifelong devout Catholic and cared deeply about religion. He tried to express Catholic values in LOTR.
“The Lord of the Rings is of course a fundamentally religious and Catholic work; unconsciously so at first, but consciously in the revision. That is why I have not put in, or have cut out, practically all references to anything like ‘religion’, to cults or practices, in the imaginary world. For the religious element is absorbed into the story and the symbolism. However that is very clumsily put, and sounds more self-important than I feel. For as a matter of fact, I have consciously planned very little; and should chiefly be grateful for having been brought up (since I was eight) in a Faith that has nourished me and taught me all the little that I know.”
– Tolkien
The Fellowship’s plan was ‘try to do what is right, however hopeless it seems’. Perhaps God will intervene, or perhaps He has some larger plan, even if you fail.
Also, we are looking back at Tolkien’s work in the light of Dungeons & Dragons, fantasy gaming, vast numbers of fantasy books and movies. Tolkien may have inspired all this, but his works don’t fit into that mold. People today tend to think in mechanistic, materialistic gaming terms like, ‘a Ranger has x abilities and y weaknesses’, ‘a Wizard can cast such-and-such magic spell, which requires n magic points, an Elvish ring, and a magic Staff’, etc.
This is NOT Tolkien’s world.
“The realm of fairy-story is wide and deep and high and filled with many things: all manner of beasts and birds are found there; shoreless seas and stars uncounted; beauty that is an enchantment, and an ever-present peril; both joy and sorrow as sharp as swords. In that realm a man may, perhaps, count himself fortunate to have wandered, but its very richness and strangeness tie the tongue of a traveller who would report them. And while he is there it is dangerous for him to ask too many questions, lest the gates should be shut and the keys be lost.”
– Tolkien