You will definitely get most discussions in a pessimistic mode if it's about the topic of Bitcoin going to zero. Who's going to be optimistic about that topic if it's useless because of it being zero?
When it becomes zero, people think that there is no more use on it and whatever purpose it has got is done then we will have to find another the same thing as Bitcoin that could grow in value over time and will also have the use case that we, everybody needs. But are we gonna find something as valuable as bitcoin whenever it becomes out of the league?

I don't think that we'll ever find something the same as Bitcoin because it's one of a kind. There have been other projects the same as is but never had been the same or at least close to Bitcoin because it is unique. So for my life if it becomes zero, just have to move on and do whatever I wanna do in life basically will just continue.