btc is the king of all coins so if you say goodbye btc, I think you are in a hurry, because if btc ends, allcoin will also end
Yes, it will most likely have a huge impact on prices - and the market might take long to recover, but it will not be the end of all altcoins, especially those with products to show (e.g. Veritaseum, Populous, etc.). Most cryptos are not cryptocurrencies, but tokens that can be used to unlock multiple, blockchain-based use cases regardless of the prices. The use cases are wide and extensive - way beyond the 'store of value' the Segwit + LN hack are aiming for - completely contrary to what Bitcoin is supposed to be, namely peer-to-peer, electronic cash. Luckily Bitcoin Cash (BCH) is going to replace BTC as the real Bitcoin before long (2019-2020).
Well, reckon I should have sold at 9900, damn vacations. With that said, I refuse to sell until it's atleast back at 9k. To all of you other folks panic selling, have fun taking the losses.
Edit: for those of you HOPING that bitcoin crashes, you're working against bitcoin. You wont see adoption from businesses until it's somewhat stable. As a business owner, drops like these hurt pretty badly if I'm not exchanging for fiat on a regular basis.