Mate I was almost going to pitch myself until I read this.
I'm not just a native English speaker, I'm competent with the language, I've studied the craft, and I can write any kind of fluent English you need, sales copy included.
Then you pointed out that you don't think that's important. You don't care about the time it takes to learn that skill, or the quality of service provided, "because it shouldn't take that long to write".
It shouldn't take that long to fix your busted hot water cylinder when it's leaking all over your new carpet at one in the morning, but I bet you don't tell the plumber that.
What you've said here is a red flag that tells me "do not work with this guy".
In my experience, clients who show that they don't value their writers with "shouldn't be that expensive" and "because it doesn't take that long" language are horrible to work with. They flake out on the job 9 times out of 10, and if they actually do follow through on a deal, they're asking for the moon while nickel-and-diming the price at every chance.
No thanks. I'll go work for the guys that throw around four and five-figure jobs without any of the hassles.
Want to know why you're getting garbage writers? Because you're attracting garbage writers.