I don't see Bitcoin replacing fiat entirely, least not in this form and not for a very long time. in future, it may happen, that to accomplish offchain transaction, we'll accept some trusted 3rd party.People need time to get familiar with any new technology like bitcoin. Many people do not want to take the risk in the case of their wealth and money that is the reason bitcoin still new to many people.

immerse in a world of continuous changes, and that is why I prefer to be very cautious about my foresights in financial matters (bitcoin included). But I tend to think that nothing will be as we are thinking and future holds great surprises for everybody.
 agree when you say that bitcoin transaction will have a faster than today, and I also felt that the price of bitcoin will rise very high in the future. most likely all places will accept bitcoin.
so that you need to earn more so that you earn higher profit

happy earnings