I think the price of bitcoin will not affect the fiat. Fiat will stay the way they are, and if the price of bitcoin reach $10.000 i think many people will start using bitcoin. Realy can't for image the on the day.
I think no. If bitcoin price will be $10,000, then most of the bitcoin users will just convert their bitcoin into fiat.
Yes more people will entered bitcoin world but their primarily purpose is to gain bitcoin then exchange it to fiat which is $10,000 exchange rate if ever that will happen.