If your interested in investing you should really ignore anything to to with adoption. If the current price was $5, bitcoin could still have all the utility it has now in the marketplace, velocity would just have to increase.
Bill Gates could store half of his net worth in Bitcoin at $5 each?
no.
I suppose he couldn't do it at $125 each either, could he? Is it possible that someone could at $125 but not $5? Wouldn't that mean less utility at the lower exchange rate?
yes, there's a lot of value in getting bitcoins value high.
Bill Gate is valued at $72.7 Billion
so assuming there are ~12 million bitcoins, bitcoin would have to be about 2666.66666666666 to accommodate half of Bill Gate's net worth.
but bitcoin has to hold most of my networth too... so 3K / bitcoin is necessary!
its always fun to do bitcoin math.