Well, to answer this, you have to ask what the market-cap of bitcoin is likely to be in the "success case" (the fail case is less interesting
).
A couple ways to look at it:
1) Compare to the M2 money supplies of various countries. Let's say a "success case" is bitcoin achieving the same monetary use that occurs in an economically "medium sized" country. Like, say, Denmark (#33 by GDP) or South Africa (#29). They both have M2 money supplies of about $200B. So if the same economic activity that these countries do ends up getting done over bitcoin, it can be reasonably asserted that bitcoin's market-cap would need to be about the same as these countries' M2 (disregards lots of factors, but this is a napkin calc here). At full 21M BTC issuance, we're in the $10,000/BTC ballpark.
2) Compare to gold, with it's $6.6T market cap. 5% of that is $330B. That's about $15,000/BTC at full 21M issuance.
3) Estimates of "off-shored"/"hidden" fiat wealth are around $30T. You do the math on this one.
That roughs out a minimum "success case", in my opinion, of 1BTC >= $10,000.
So then how much fiat wealth do you consider "a lot"? If a million bucks does it, you need 100BTC to make this bet.
