Do you think that if we all hodl, the value of coin will go up?
The strongest reason that holding Bitcoin is better than holding Shitcoin,
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.
They have not felt regret, big losses and stiffness in their minds about the Shitcoin they bought. Market dominance is controlled by Bitcoin so there is no reason if they don't have Bitcoin in their portfolio. Although sometimes it takes them a long time to make themselves aware that investing in Shitcoin will bring them to Rekt. But if they realize it earlier it's certainly better because they can use the money to buy Bitcoin instead of losing everything if the Shitcoin they hold goes to Zero.
I understand your point. But everyone has their stages to reach the final level in Bitcoin investment before they sell their holdings. In this pattern everyone is looking for a profit in their investment and if they already get it will probably sell their Bitcoin holdings and Buy again at a lower price level. Everyone is looking for profit and not to hold it for life because we need to enjoy the benefits of our investment to buy what we dream of in our life. I explained that everyone has their own stages and has a target for when to come out and when to buy again.