That's true most of folks are not bothered with emergency funds that much because their guidance usually act like one for them, like some one who is still leaving in Under his parents roof and same time accumulating Bitcoin for instance, are in advantage . Because their parents are going to be one taken care of their need while they use their allowance to accumulate Bitcoin, especially when the folk have a well paying skill that can earn he or she some extra bucks .
So for such person emergency funds is not completely necessary, because their parents has already being playing such role for them in taken care of their needs and stuff .
There is a big difference between self-reliance and dependency. As you said, there are many who want to invest their entire income in Bitcoin, they do not think about an emergency fund because if they ever need emergency money, their parents will provide them with that money.
Yes, it can be, if there is more than one income in a family, one is less and everyone is dependent on everyone, then they can invest in Bitcoin from the remaining income after excluding basic needs and emergency fund money.
However, it should be remembered that the amount of money you are saving in an emergency fund for one person, if you want to save for five people at once, then you will have to increase the amount of money in the emergency fund.
Just as investment is important for survival and meeting financial needs in the future, so is the importance of an emergency fund.