Yes, this makes sense. Bitcoin is probably not suitable for replacing every and each fiat coin in the world right now as it is and make an unique, universal coin... So another coin will probably replace it, or Bitcoin will evolve so much that it will make no more sense to call it Bitcoin. Only future will tell.
We could not tell what would happen unless it happened in reality. Meaning that the future of Bitcoin is actually broad and not specificm it could make a huge development, progress and growth by simply increasing its people support or by developing through the age of time and technology. So if this happens we do not know what is the next thing to do. So for me the best thing to do is to trust and believe on Bitcoin fortune by simply having investment and trading so that you vod have a chance to have profit and earn out of Bitcoin development.