I also heard that a lot of Mt. Gox victims sold their accounts for a couple of dollars because they thought it was not worth anything anymore. But, I am not sure who was the buyer and if they got some benefit from those accounts.
If this is true, then they have something to regret all their lives. I wonder if they did KYC when they traded there; there is a possibility that they will contest the buyer of their account and ask for verification to recover those accounts. I mean, we never know the character of these sellers because the profit is too huge not to do something.
Cashing out is the right thing to do, but given how Bitcoin has performed in the market all these years, you would not cash out all of it. You expect a better price in the future; that's when you will cash out.
They are OG Bitcoiners. So, I believe they have a understanding of Bitcoin market and I want to believe that most of them will end up holding a tiny portion of their holdings for the future. We never know what could happen in the future. If you ask me, I would have hold at least 10% of it for the future.
I think it depends on the amount of your holding back. In the old days, it was easy to hold 1 Bitcoin. I'd like to believe many of them are two-digit, four-digit holders of Bitcoin. If I had 10, I would retain 50%. I already made a huge profit from half of my share.