On the contrary, if everyone or almost everyone held their coins the value of bitcoin would skyrocket seeing as they were so rare.
The same could be said about tulip bulbs.
Resources must be not only scarce but also valued. The problem of "everyone just hold!"
is if that becomes the ONLY reason to hold, it is unsustainable.
Bitcoin is quite a bit different that tulip bulbs for numerous reasons. Using bulbs as a currency would obviously be a bit silly but that was just more of a wild investment that went sour and collapsed. Bitcoin is already a currency with a fixed supply whereas tulip bulbs wern't. Of course bitcoin could still colapse but tulip mania and bitcoin are two completely different models.