Hypothetical question:
What if everybody wanted to move from USD to BTC? Wouldn't the dollar become completely worthless after a certain number of people switched over, making it impossible for everybody else to convert their money?
Not impossible, but harder. You'd probably have to get around 90% or so, before it'd became 'impossible'.
However ...... when you said "hypothetical", you kinda nailed it there.
I mean, hypothetically, if water started turning into wine, wouldn't wine merchants have a hard time making money?
Or, hypothetically, if I won the lottery, would I still have to go to work?