Because the pools of capital that will soon be allocating to bitcoin are much larger than the pools of capital that were allocating to the retail rips. Also, those pools of capital will not be trading, they will be holding (per mandates) for 5-10 years.
Also, the legitimization of the asset that comes from traditional institutions participating.
Finally, the absolute scarcity and Bitcoin hodlers inclination to hodl the majority of their stack, whatever the price.