Well, we have senior colleagues here who will share their various perspectives on this, but I will also say something about it.
Many investors will not have invested if all cryptocurrencies are marged together as you suggested, and the cryptocurrency community/world will have no competition, hence Bitcoin will have lost value by now.
However, the introduction of Altcoins has made crypto a topic of conversation in numerous countries around the world, as well as ensuring that Bitcoin retains its value and the trust that people have in it.