The purpose of Bitcoin was created in my opinion not to challenge Gold and Fiat but to provide convenience and transparency in transactions and no one can regulate or simple language is a digital currency that is completely controlled by the user.
So, it has nothing to do with Bitcoin challenging Gold in 20 years and challenging currency no. 1 world in 50 years as you wrote.

If you have other intentions behind this post, it's better to be clear.
Please read Satoshi's white paper or you can also read bitcoin.org for a general explanation.