am not sure if bitcoin will survive that long , because there will be surely another currency that will make its way to the top as there are many issues bitcoin network is facing and if all of those leakage will be covered by a new coin then what will hinder to break bitcoin position and bring this once great coin to the lowering position.
100 years is way too long to predict, but just if we conclude for the next decade bitcoin will be there and who knows it still could be a leading crypto currency just like now. But yes some or other currency may have more demand than btc considering the price but still the king of all might not go away so easily as far as I understand it.