To clarify, I'm not saying that it's possible to learn to write without writing a great deal. I certainly wouldn't have learned to write well without writing often.

However, I didn't learn to write particularly well until I was out of college and had begun writing for myself. In school I was rarely interested in ensuring that what I was writing was interesting, well-phrased, or enjoyable to read. Those qualities simply weren't prioritized, which is weird, because those are the qualities by which writing is judged in "the real world".

I certainly relied on basic writing practice I received in completion-based classes, but my claim isn't that I didn't learn anything useful in school, it's that the time I did spend in school was poorly allocated and resulted in an underdeveloped product.

"If children started school at six months old and their teachers gave them walking lessons, within a single generation people would come to believe that humans couldn't learn to walk without going to school."

So competent writers generally did not learn that skill in school. At best they learned some foundational skills. But the competent writers that I've known, often think that there were betters ways in which they could have learned those skills.

I have sometimes been accused of writing competently. And so it should be no surprise that I agree with them. School was a terrible way for me to learn. And I credit most of my skills to things that I did outside of school.

This goes doubly for homework assignments. As https://www.alfiekohn.org/homework-myth/ explains, research shows that homework is useless overall. It can help, or it can hurt. And on average it balances out to no net benefit.

I have ADHD. This reduces the odds that homework helps and increases the odds that it hurts. Growing up, homework was a constant burden on my life. I would have been far better off if I'd been given less homework. Particularly homework which looks like a practice drill.