How is this even possible? Bitcoin all mined, and at the same time all lost? Well, I have read enough replies from people and I wonder why they even bother themselves with many of the suggestions since this is what will never be possible, it can't happen. Who stole them and where did they store them? For what reason and value did they steal them when they wouldn't be able to spend them?

Bitcoin is not a kangaroo blockchain and system where there will not be an explanation for what happens. Not this time what people thought was anonymous is no longer anonymous. The worst that could happen is for a bad news break to the extent that people do not want to deal with Bitcoin again. By this, the value will fall so much, but even at that, some people will still be adamant and will not sell their coin and continue to hold it.

And who knows, there could be a shift in the event and the coin gains back. Which will be a second chance for those who hold it to gain more. I do not see anything that can even cause total disappearance here. Also, on the second thought, can Bitcoin be 100% mined? I doubt that as there will always be divisions of mining and will go on like that unless the whole system crashes, which I don't see feasible for now.