Basically, they are expecting that the price will grow as they sit idly on their hands. But this growth is not possible without other people actively using bitcoin, paying with it and selling for it - all those people who help create real value of bitcoin. And I know what hodlers are going to say in reply. That they diminish the supply and thus also contribute to this growth.
That make sense surely. I mean without any trade of the coins for real use there will never be rise in the value. The more demand we create by using the crypto the more value it will gain over the time and that the truth about it. I mean if we have 100 X coins and people are buying them then they will be adding the value because they are buying it and putting money into it. But the actual value will rise a lot when those coins will start trading amongst the people or investors and as soon as it reaches to 80 X coins or more then demand will suddenly rise and thus value will follow as well. This is just my way of looking at it and I guess this is what OP is also trying to say here.