Suppose that the USD supply was limited to just 21.000.000 USD for the whole planet and the whole existing money supply.

Given that the USA current debt ceiling is standing at 16 TRILLION USD, just to cover this debt alone, the value of each "limited supply dollar" would have to be 761,904 "unlimited supply dollars".

It seems to me that in the long term there can only be two possibilities: either bitcoin will just disappear or remain the play-money of a very limited geek group or will rise in value to the six digit value against the "unlimited supply dollars".