Bitcoin is better than shitcoins and not everyone knows this, so not everyone is keeping their bitcoins. There will not be a time when everybody into bitcoin will be keeping their bitcoins, because not everybody that has bitcoin has strong discipline to keep it, and some others know bitcoin for use as transaction, and there are also the people who are more focused on keeping altcoins instead of bitcoins. For that reason, no matter how much people say an investor in bitcoin should keep their bitcoins for as long as possible, everyone will not still be able to keep it. There will always be people using bitcoins and not just keeping it to increase in value in their wallet.