Yes it is the leading he crypto currency and will still be leading for ever because no coin can contest in term of price and popularity with Bitcoin, if Bitcoin increase other coin increase too, and if Bitcoin decrease they also decrease too.
Bitcoin is the first crypto currency on the Blockchain so it is obvious that it will be leading the market though we do not know if it will last forever. In terms of price, there is no way that it will be second since Bitcoin is the most popular and the most used and traded digital currency of all time. Though I don't know about your last statement since there are a lot of times that other crypto currencies pumps while Bitcoin dumps.