If this were to be the case, why would people spend Bitcoin at all? In this theoretical time, wouldn't it just be a poor financial decision to do?
There should always be selling for bitcoin to have a good market circulation. If there are only a few who will use it, few merchants will accept bitcoin as payments.
In some cases, people need money leaving them no choice to sell it.
Others also want to take chances of the dip. Selling it at a high price they consider will give them a chance to accumulate more when the price goes dip.