first, there is no such thing as gold and silver in crypto's, you should check why ppl are investing in physical gold/silver in the first place.
It's, uh, a metaphor.
second, you should check the recent charts for btc/ltc and you will see that ltc in fact does not follow btc.
I don't think you quite understood that chart, lol. It
precisely defines the current relationship between the two coins. They follow each other, but the ratio of relative values changes over time it's not a simple constant relationship.