Except this isn't nearly enough. Email is quickly becoming like the SEO industry. It's not just enough to "have great content" to ensure you're ranked highly.
You have to manipulate it at the whims of the search engine / email provider.
You have to manipulate it at the whims of the search engine / email provider.
If you only send mail to people who have willingly opted in, not through trickery, pressure, inducement or some BS promotion, they'll actually want to read your mail and won't tolerate it being binned with the SPAM.
Unfortunately, a lot of business people don't get that.