If bitcoin is the only world currency and money velocity is constant, it will rise/fall by the same percent as the world economy. We already have a similar fina

If bitcoin is the only world currency and money velocity is constant, it will rise/fall by the same percent as the world economy. We already have a similar financial instrument - Vanguard total world stock ETF. Why this ETF does not produce a deflationary spiral? I think the answer is the same for bitcoin. https://personal.vanguard.com/us/funds/snapshot?FundId=3141&FundIntExt=INT#tab=1 https://personal.vanguard.com/us/funds/snapshot?FundId=3141&...