Let's imagine that Jack is right for a moment. He is right by the way. Between now and "The Transformation", everyone on earth is in a game of musical chairs when it comes to fiat and Bitcoin. A tipping point will come where no one wants fiat any more and everyone wants Bitcoin.
If you think that is impossible, think about the Zimbabwe Dollar. No one will take them for Bitcoin (or anything else) because that money is past the tipping point. Rather than switching to Bitcoin, they use US Dollars and Euros in Zimbabwe. This will happen on a global scale.
The only money that has lasted throughout history is gold. Every fiat currency ever issued has gone to hyperinflation and vanished. Now with Bitcoin, fiat will never emerge again, because Bitcoin will prevent it. The US Dollar is the last big fiat money to ravage the earth.
People talk about "Bitcoin on-ramps". What they in fact are talking about are "Bitcoin off-ramps", where people escape from fiat into Bitcoin, which cannot be corrupted, or revoked.
When this happens, there will be a fortune made on providing those off-ramps. The policies and prices quoted at ramps will be the indicators of how far into The Transformation the world has gone. When they stop taking fiat, you know it's over, and the Transformation is complete.
For the record, Bitcoin is not slow. Bitcoin is not expensive. You need to look at it next to other services to make a good comparison. Bitcoin is extremely fast, even with 4 hour confirmation times. It is super convenient, and payer fraud is impossible. Bitcoin fees are low.
Bitcoin, like all software, is not static. We are at the cusp of the dawn of Lightning, which will change everything. The current transaction per second rate will be shattered forever, as millions of transactions per second are made. This is going to happen. It is inevitable.
All objections people mount to say Bitcoin can't work will be overcome. If you want a glimpse of what's ahead, look to the Elements Project elementsproject.org but even that can't predict Golden BB products like OpenDime, which radically alter and improve Bitcoin's utility.
What we know for sure is that all fiat dies, the dollar is fiat, the dollar will die. In the next hyperinflation, gold will remain behind (it's always left behind in hyperinflation) and this time, the different element is Bitcoin, that will prevent the re-emergence of a new fiat.