It's a feasible argument. But, this is such a 2009 - 2013 perspective to take on Bitcoin. Quite immature and naive when you consider all that we've learnt about this market from 2013 and onwards.

Quite frankly, Bitcoin doesn't need to replace any established Fiat currency to be 'successful.'

Just imagine how ridiculous it would have been if the EU had ran some promotional campaign, promising that their new currency 'The Euro' would "replace the dollar" within 15 years. It would have been a foolish statement to make, because the point of a currency is to promote and enable economic activity - not to compete with other currencies.

By continuously touting this "Bitcoin will replace the dollar" nonsense, most people are forced to miss the more important bigger picture.

Bitcoin is the first, globally recognized currency of the internet.  

In the years ahead, this will have a much bigger impact on world economics than it does currently.

So I state again, Bitcoin is not in competition with the Dollar. It is designed to be used in tandem with the fiat currency system, not as an alternative. This is very important, if you can grasp what this means - as far as the internet is concerned.