If you give an LLM enough context, it writes in your voice. But it requires using an intelligent model, and very thoughtful context development. Most people don't do this because it requires effort, and one could argue maybe even more effort than just writing the damn thing yourself. It's like trying to teach a human, or anyone, how to talk like you: very hard because it requires at worst your entire life story.
Why the f- would I train software to do my thinking and reasoning for me!?
Something that freaked me out a little bit is that I've now written enough online (i.e.: HN comments) that the top models know my voice already and can imitate it on request without having to be fed any additional context.
There's a data centre somewhere in the US running additions and multiplications through a block of numbers that has captured my voice.