There may be reporting bias going on. I suspect a high percentage of people who lose BTC by themselves will report it in a forum, since, as far as they know, th

There may be reporting bias going on. I suspect a high percentage of people who lose BTC by themselves will report it in a forum, since, as far as they know, their case might have unique details in which a more knowledgeable person might find a solution. But a low percentage of people who lose BTC due to an exchange hacked will report it, since the information they need is already in news and blog posts all over the web.