The scenario of crypto suddenly disappearing completely is impossible, there is no viable reason or hypothesis that suggests it could happen. But a major collapse like the tulip bubble or the dotcom bubble is possible and we should not be too subjective.
Although there is a huge difference between dotcoms and bitcoin, because bitcoin is a decentralized asset not owned by any company, and its value is based on scarcity and trust in its network. But what they have in common is excessive speculation, and this can easily lead to a major crash if speculators withdraw their capital en masse. That would certainly cause serious damage as well.
The fingerprint crypto has mark on the faces of earth, it will be difficult for it to disappear from the surface of the earth. The only thing that can make crypto disappear is if the internet refused to work and since that's not possible then even crypto can't be taken away from the surface. There is no regulation that control crypto, it's not an illegal thing to do, it doesn't affect government in any way, it doesn't manipulate people neither does it obstruct justice.
If there is concern about SEC today that crypto are securities and are not following what the government want, people will pivot to crypto without team, there might be team in real essence wouldn't act like there is any people working on it but just some group of people that want to achieve a common goal. There are plenty of other reasons people will used to bring crypto alive if government want to bring excuses to stop crypto from existence.