Did you know that Chinese didn’t have a word for “She” until about 100 years ago? In fact, Chinese operated without a female 3rd person pronoun for thousands of years, and it wasn’t a problem – until interaction with the west. Watch this video to learn the fascinating (albeit winding) history of Chinese gendered pronouns.
You are misunderstanding. We can talk about adopting linguistic conventions in terms of orthography and vocabulary for example, but let’s look at a practical example of completely unintentional change in grammar and phonology.
In Latin, there were 3 genders: masculine, feminine and neutral, marked at the ending of words. In the descendants of Latin, the same spontaneous changes that create different accents of the same language happened to make the neutral ending sound identical to the masculine one, and so they were merged.
There is no series of choices, no magical void.