If your talking about butcoins era, it will last for a hundreds of years? More or less, because they are the first and the most successful crypto currency. And our society are somehow accepting them as a real currency. I know in the future it will be our official currency rather than paper and coin. We will use the virtual ones.
Our currency can be digital but it surely wouldn't be bitcoins. We are controlled by the government and bitcoin is not issued by any government. We do have virtual money or digital money but it's the same thing with the fiat paper and coin that we have, just in different form.
I want to mention that bitcoin is the most successful cryptocurrency and it's also the first, but we had currencies back in the days that we thought was the best currencies. Hundreds of years ago, no one could have predicted that we are able to send money without having to meetup. No one could have predicted that we will be able to talk to each other even if we are thousands of miles apart. So if you think that bitcoin can not be replaced after a hundred years, you might want to think again and maybe even consider that technology is growing quickly.