Just consider what you'll do if Bitcoin absolutely crashes. Are you going to start investing in alternative currencies, or are you going to stop investing altogether? Every regular person who invests in cryptocurrencies experiences the same response. The technology that connects the cryptocurrency world is known as blockchain, and Bitcoin is to thank for its introduction to the public. And Bitcoin, the dominant cryptocurrency, is the most dependable digital asset. Trust in the crypto realm is undoubtedly shaken when it fails. I have no idea what the future holds, but I think that at some point, this may be the pivotal moment. But I guess it won't be the end of crypto because the world will certainly be willing to embrace the concept of crypto.
Even if the concept doesn't die off, the technology called Blockchain might remain and be revived, but if Bitcoin crashes and vanishes, altcoins won't be able to survive because people would sell their altcoins as a first when they see Bitcoin crashing badly since the whole market knows that altcoins move along with Bitcoin. When it goes up, they go up as well, and when it crashes, they can't stay profitable. So, when something like that starts happening, altcoins will be the first ones to crash.
However, once the dust settles, people and developers will obviously start working on cryptocurrencies again, and there will be a new beginning for the industry. However, it won't be the same this time around if there is no Bitcoin, most people might not have any interest in cryptocurrencies after that.