
Samurai Jack had 52 episodes over 3 years. Naruto had over 220 episodes over 15 years. That's not counting any of Samurai Jack/Naruto's additional merchandise, such as the manga, toys, games etc (which Naruto still has sold more of).
In case you're not aware, TV shows aren't kept running because they're good. They're kept running because there's an active viewership which allows the advertising space and merchandise to be sold.
Also, I'm not a Naruto fan. Just wanted to point out something about the modern day market.