I get it that people have cold wallets that haven't been used for years, and also understand they don't want to pay tax over their coins, but at some point if you want to cash out or buy something, that's where the fun starts.
How does one explain where the coins came from.
That's actually a good question.
I have been holding a large part of my coins offline for years, and will very likely continue doing that endlessly. I know it may sound weird to some people, especially because of the fact that the general opinion is that why would you hold something that you will never sell, but that's my choice. I aim at the moment Bitcoin becomes an actual unit of payment and store of value, which it is already, but then on fiat and Gold level.
I don't want to expose myself to the potential risks of an imploding fiat system where my fiat wealth will be turned into dust. I have basically taken a life long hedge against the current system, and I'm very glad I did and do so. In other words, I don't look to cash out anything. I'll deal with the legal matters later when Bitcoin has grown to what I believe it is capable of. I have a seperate stash that I use for trading purposes on centralized exchanges, which I do pay my due taxes for. These coins I can put to work in any legal manner, so I'm not at all worried.