If cryptocurrencies disappear - how will your life change ?
This is called an impossible hypothesis since the didn't explain how it could happen. The only possibility is that the internet and electricity go out across the entire planet, possibly due to a meteor or a collision with a neighboring planet, and we lose all the servers that hold copies of the blockchain. If someone can explain how this scenario could happen, I can then consider how not just my own but all of our lives would change.
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.