I don't suggest just reading code, I suggest reading code critically, with an eye to how it can be improved.

You're right that casually reading 10 blog posts doesn't help one's writing. But reading them carefully and critically, trying to concretely identify how the author has crafted the language to support their goals? I believe this absolutely can improve one's writing; indeed, I think it's an important part of improving.

Yes, of course, you still have to knuckle down and do a lot of writing at some point, too :)