I think reading and writing somehow belong together. Normally you probably start with reading books, often you stay with it. Now and then, however, it appeals to you to write such stories yourself. Stories that have moved you, that have been fun, that have distracted you from your stressful everyday life,... You want to try that yourself and bring your stories to other people.
I think very few people start writing because they want to earn money with it. First and foremost, it's about bringing your stories closer to other people or because you feel the same way when you write as you do when you read (stress is reduced, you forget about everyday life,...).
At some point you will surely reach a point where you want more. And what comes after reading, after writing - a publication.
I think you can compare it well with sports. I saw my father playing soccer, then I started playing myself. Later I earned a little money with it and at some point I wanted more. For me, this is a very natural development that happens in many areas.