If serious regulations, massive sell-offs, negative portray of media and etc would happen, then it's possible to happen. But I don't think that is likely to happen. In its core, blockchain technology is pretty much like the internet. It's created by a mesh of networks that won't shut down unless every device connected to it would be corrupted or shut down. Altcoins may shut down much easier but the whole crypto won't go away as of now.
That's certainly true, mate. Nowadays, crypto is too big to fail. The only way for it to go to zero is if fierce regulations cripple the entire industry in an instant. Since governments cannot reach a common agreement, this seems largely impossible. It's evident that companies and businesses are adopting Blockchain technology for their own benefit. As long as crypto's core technology is being actively used within the mainstream world, then there's no reason why it should go to zero in the first place. It's odd to see many people saying that crypto is going to zero (like Ethereum's Vitalik Buterin) as the aforementioned facts tell otherwise. This could be a result of FUD, because of crypto's price volatility across the market.
Nonetheless, the more people join several blockchain networks, they stronger the crypto industry will become. In effect, it'll be impossible to take down everything (as it's the case with the Internet). With many exciting trends within crypto land like stablecoins, Lightning Network, smart contracts, and more, I believe that crypto will continue to grow "to infinity and beyond". Just my thoughts
