I don't think so, Bitcoin will remain to the top highest in the market and if you check the chart for Bitcoin at this moment you will be satisfied. I believe Bitcoin will exist a long time because it is popular now and a lot of people invest for it that's why it's hard to defeat Bitcoin.
The face that bitcoin is on display in the market, it is convincing people that defeating bitcoin is unfounded and doesn't have any chance in 2019, even the deepest impression we can see is that bitcoin is confirming new numbers, numbers that overwhelm the altcoin market, capitalization has mostly revolved around bitcoin, very little capitalization is poured into altcoin. The story of defeating bitcoin is not happening, what happens is just a serious failure of altcoin, many altcoins can no longer survive in the face of the onslaught of bitcoin.