Why do I read so much? Because I can. Something like 14% of the world's population are totally unable to read or write. An estimated 32-million adults in the United States are functionally illiterate - unable to read and comprehend, unable to read understand and reply to basic questions on something like a job application.
Because of the way my brain is wired, I learned to read without learning to spell. This mystified teachers in our rural schools. I didn't learn reading in the way they had been trained to teach it. We fought over this for a couple of years. But within a couple of years reading clicked for me, and the teachers tolerated my spelling, because I clearly I understood. One of the reasons my handwriting is terrible, was to cover up my spelling. When I started taking college classes I spent a semester working with an expert, who assured me what worked for me, worked, and taught me new ways to approach spelling (this was in the early 1980's prior to spell check.)
I didn't really become a heavy reader until my 20s. I discovered a world of knowledge and entertainment between the covers of a book.
Computers and spell check changed my world. In the late 1980's I bought a Panasonic typewriter with spell check and about a 10 page memory. As I recall it was about $400; a couple of weeks pay for me at the time, but it changed my life. Moving on from there to computers I have become much more of a writer. And the more I write, the fewer words end up underlined in red. Some days I get to nearly 100% in spelling, but I don't worry about it.
If you want to improve your writing, do two things, read more, and write more. I learn from reading, new ideas, new ways of assembling ideas, new characters, or styles. The more I write the more naturally my writing flows.
I can think faster than my fingers can commit those thoughts to the page. I can read faster than I can talk - I read about 50 pages an hour. My brain sometimes assembles thoughts in odd ways, and this ends up in convoluted sentences, that communicate the point, but sometimes with the wordiness of a victorian novelist.
I really should listen to recorded books. I have over the years, but haven't for several years. When I was in law school, the public radio station in Louisville broadcast the Radio Reader, at 9:00 PM each night, I would go to bed, set the radio to shut off in one hour, and fall asleep to the spoken word. I remember not wanting to miss a minute of "The Perfect Storm." A novel I probably wouldn't read, but so enjoyed listening to.