I think the biggest problem is that most of the English curriculum after basic grammar and spelling (at least in my experience) is like 90% reading and 10% writ

I think the biggest problem is that most of the English curriculum after basic grammar and spelling (at least in my experience) is like 90% reading and 10% writing about the things one just read. While reading is clearly a necessary component of writing, it is equally clear that one does not learn to write by reading. One learns to write by writing, and I doubt that the average American student is doing nearly enough writing to actually become skilled at it.