The two aren't comparable. Bitcoin has earned its success through innovation, fundamentals, infrastructure all that. Litecoin has none of that and was just the 'me too, me too' coin riding Bitcoins coattails. Litecoin always was a ripoff shitcoin that had zero innovation. It got the attention it did because of good marketing 'silver to bitcoins gold' and timing in particular with the last bubble. I personally hope it dies the death it deserves as people flock to truly innovative altcoin whatever that might be.
It was merely an experiment. It tackled two of the main things criticized when it comes to Bitcoin: PoW algorithm and confirmation time. As it become apparent, that those two things aren't that big a point of failure as though (and Scrypt ASICs are also emerging) it became less unique. And if we really should opt for another currency, we might go for another altcoins to begin with!