Bitcoiners are gambling that other Bitcoiners are not going to dump coins on the open market at any given point.
You’re gambling they understand the implications of 21M. That they understand fiat will continue to be printed. That they understand how consensus works.
If those things (and possibly others) fail, Bitcoin is no different to any other asset and it’s a race for the exits. But if people understand them and they hold, over time, more will understand them and that will reduce supply which will increase spot prices reinforcing the incentive to hold.
Bitcoiners are gambling on the HODL wave holding up. That’s the best proxy for decentralisation without which, it all goes to shit. You’re betting the OGs peel off fewer coins with each order of magnitude, and more will adopt it than sell it buying time for everything to be built around it to supplant fiat.
None of this is certain. It’s all unquantifiable. But if everyone loses faith and you’re alone in Bitcoin - it fails.
It is nothing without the network of people who believe in it, who have decided it is their money, who will put their energy into it and go to war for it whatever their reasons.
You cannot be a Bitcoiner alone. Without other Bitcoiners, there are no Bitcoiners.