Jiraiya was a failure too, when he was a genin/chuunin. Failure isn't that right of a word, but lets say ''a diamond in the rough''. Itachi was way too self sacrificing for his own good and, for whatever reason, he mind****ed his younger brother and annihilated his whole clan. Minato was a ''girly, flaky boy'' when he was in the academy.
You can find flaws with every charachter in Narutoverse. Naruto, Sasuke, Sakura and the whole generation are still teens flung into the middle of war. They all still have a long way ahead of them. Ability-wise and personality-wise.
People that actually live for a reason?
Come on!
I wonder how you came to the conclusion that neither Naruto nor Sasuke have a purpose in life. Naruto's aiming for becoming the next hokage, creating peace and the retribution of Sasuke. Sasuke is aiming for furthering his revenge against the people who had his clan eradicated. You wanted reasons, so, there they are.
Oh, by the way, Naruto can do it all.
He beat Pein, destroyed two kages, ripped the chakra out of the kyuubi, became a sage, fused the rasengan with his affinity, saved the whole joint army from the Zetsus and now is battling against 6 jinchuurikis and one badass mofo named Tobi.
Sure, he got help, had his ass saved loads of times but that's the reason the shinobi work in cells.
Same thing goes for Sasuke too. He accomplished great (usually horrifying) feats, but without the assistance of Karin, the other members of Taka or Tobi (who got him out of a certain death situation more than once) he would have long since become worm food.
If they both had soloed every opponent they came across until now, Kakashi's whole teamwork and trusting comrades speech would have been pointless.
Plus, there wouldn't be much excitement left in the fights, would there?
