Bitcoin price is not influenced by Alltcoins, it has own price which very strong and unique because it was created with good foundations. The price of bitcoin depends on the market demand and supply of bitcoin itself. It means that the holder of bitcoin influences the price. However, as the coming so many altcoins todays it has impact to bitcoin price because many investor are move or even spread their money in altcoins. So, when the number of investor of bitcoin is decrease automatically the price will high. It is not threaten, that is my opinions.