We can't tell what will happen to Bitcoin in the next 150 years. Maybe the price will increase further and become more stable. But what we are certain about is that almost all of us here will be dead by then and will not have the chance to enjoy what Bitcoin would become by that time. For now, let us keep investing for ourselves and our next of kin. As each day passes, let's embrace the beauty of Bitcoin and let the future decide for itself. Bitcoin has come to stay and we still have a long way to go with Bitcoin.
I don't think even the experts can give an exact prediction of what exactly will happen to Bitcoin in the next 150 years, because, as you said, I don't think anyone will be alive, so I don't think there is a reason for anyone to think about exactly what will happen to Bitcoin, and what we are supposed to be focusing on is now, and it should either be that you are holding or you are trading. That is one of the ways that you can make things easy for yourself by learning because most people don't want to learn, and for those that don't want to learn, I don't think there is any better way out. The best they can do is actually to learn, so they should stick their nose out. If they want to know what will happen to Bitcoin in 150 years, they should focus on building themselves better.