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.