This is because. Bitcoin was the evolution, than people started thinking on various other categories on blockchain some for real products and some for scamming by pump and dump coins. Bitcoin since was the first is trusted and now been used at various places. thus other coins got importance too and getting used.
maybe I do not understand something, but I really can agree that Bitcoin is the pioneer in the world of crypto currency. Well, about using it in different places, I'm a bit skeptical. On this basis, its value is rather doubtful. The situation can be changed only by the actual use of Bitcoin as a means of payment all over the world.