You don't get it. People who are holding these are coins in their private wallets are doing so not because it's a beautiful work of art they want to hang on their wall and show their friends, they are waiting for a price. And when they get that price they will gladly relinquish their coins...
I do get it. I've made statements here that I don't think of bitcoin as a currency but as a store of value and yes, I'm in it for the price appreciation. I have a friend who has been telling me to sell all my coin as it hit $1k, $2k, $3k.... Sell for what? Dollar$? I don't need to, I've been spending them recently on food, clothes, travel, laptops, etc. etc. I trade other cryptos which (by luck) increases my bitcoin holdings.
The nice thing about not "cashing out completely" is that the only taxable event is the amount I spend, but I take a risk that cryptos can go to zero tomorrow or whenever.
It's the nice thing about bitcoin, it can be held as an asset for speculation (like a stock) but can
also be spent in an instant (unlike a stock which takes a few days for the proceeds to clear to your bank). Another nice thing is that it's easily portable, like gold, but very easily can cross borders unlike gold. Another nice thing is that it can be sent to anyone anywhere in the world instantly. And also having bitcoin in your wallet is nice like a swiss or offshore bank account except the bank administrators don't have power over your coins or your privacy.
Ok, back on topic and the effect of futures on the bitcoin supply...