But of course, it's already proven it can do this on at least one scale. Whether or not it can do it on a larger scale is still to be seen.

This is not a chicken-and-egg problem. Initially there is some value of doing bitcoin: some find it fun, some believe in future growth and do early investment. Sceptical people join later when they see some people already joined. As number of people slowly grows, more people join after them seeing increasing value in the system. So there is no catch-22: system is unrolling completely by itself until everybody is in. If people discover some problems with it, growth or even total demand will go down.

See also my comment above about subjective value of gold.