I don’t think we are 100% sure that it will last forever, but rather we use it for a main purpose or we use it to create another way of earning money outside the crypto space, such as physical business or something similar to that, so that anytime we experience losses or bad times here, we can confidently go back there without suffering from financial problems.
In my opinion things are totally opposite. It is precisely the uncertainty in physical business and traditional investment methods that is pushing to invest in cryptocurrency. And when bad times come, such as an economic crisis, bank collapse or war, cryptocurrency can survive it and stand, since it is not tied to any national economy. Unlike a physical business, which will definitely feel the full impact of hard times.
In a typical way it is really ideal to use the source of income is the business and other assets that are more tangible than crypto because in the future the value might move not as fast but there's an assurance you can do anything on it well depends on the concept and the place of course. But today some of people today are using the technology or the crypto world itself to gain money beside of it, as long as you keep earning its good. At some point they are now doing the crypto as source of their income like trading still good run to use this to help your current status.