Email blindness is not how your eyes get sore from reading too many safelist email. In fact, the real person suffering from email blindness is the person SENDING the email, not the person receiving it.
Email Blindness is what happens when your list stops reading the emails you are sending. They get email blindness to YOUR emails.
If you think about how most people read email, the first thing they do is do an "email triage" where they delete everything that they think has no value. They look at who sent it and what the subject line and then click Delete, Delete, Delete.
If you have been sending lots of emails to your subscribers that have not been interesting and informative, then they may delete your email as well ... without even considering opening it. They haven't unsubscribed from your list, but they might as well have.
The cure for email blindness is simple. Send emails that people want to receive. Send emails that people want to read. If they associate your emails with interesting and informative content, then they won't delete it and the email blindness is cured.
Like most things, the cure is simple, but not easy. Writing interesting and informative content requires training and practice. It also requires research. That is why I am constantly working on learning new things. It gives me lots of things to write about.
If you are having problems coming up with things to write about in your niche, then it probably means that you are not reading and learning enough about the niche. The more you read, the easier it is to write.
Let me know if you want help building your list. I am here for you.