It is interesting to think that because technology has accelerated so fast in the past couple of decades, something like bitcoin would have seemed futuristic or impossible in the 1970's and 1980's. That said, it is fairly easy to imagine a world of no Bitcoin if you can remember back 20+ years or more .
There were no bitcoins 20 years before and we could imagine the world without them only before their existence. Since the invention of bitcoins, it's impossible to live without them.
I can't imagine a world without bitcoin. What if someone says, imagine a world without the Internet and you will say that the world without the internet will be the end of the world. We cannot say the same for bitcoins, but those who are using bitcoin, for them it is like a horrible dream to think of a world without bitcoins.