One person or group of persons, who's experiences and understandings in life, come up with the ideas for tools. And when they do, not every entity on the planet instantly knew and understood the purpose and function of said tool. When seeing a tool for the first time, you are not instantly filled with the knowledge of what it is and it's use, you need to either experience it first hand with experimentation, or be taught by being shown or told.

A child with an active imagination will often wish to play out a scene or story they have heard or experienced. A child doesn't just do, there are factors leading up to that. Likewise, other means of playing out roles or 'pretend' doesn't just come naturally. You don't instinctively know what roleplaying on the internet was, through forums or games or chats. There was a step before that leads you to it, and before that step was one before it.

I was an imaginative kid growing up, I would roleplay with my toys or whatever all the time, but I didn't just know of roleplaying in any sort of form online. I didn't know to just look either. I remember seeing the old forum RPs back when for the first time, and was fascinated by them. Never realized RPing in a game was a thing either until I played Tera once upon a time. And not being someone who actively seeks it out, but on seeing it, was interested in giving it a try.