OK. I have signed up using one of my Twitter alts just to respond to this.
I manage a Facebook page with 3.5 million fans. We are not considered particularly authentic in our field — so-so would best describe it.
The lower reach posts you you see is the cumulative result of almost everything you have mentioned, IMHO.
Your Facebook post count is way, way high. If Facebook actually has said you can publish 24 posts a day, they have deliberately misled you for whatever reason. We post 5-6 posts a day, and on a desperate day, 7.
Our post mix is 4 link type posts, 1 image / video post on a good day. This makes me quite uncomfortable in fact, and I am constantly trying to change that to the post ratio you mentioned. In our case, that would be 3 link type, 1 image and 1 video, more or less. I suspect not reaching that is going to bite me in the ass soon.
Next, the various Facebook algorithms. Irrespective of what Facebook says, all of them have one objective — to get more money out of potential advertisers. That requires a constant decay of your reach. There is nothing you can really do about it. It will happen, even if you follow Facebook’s spoken and unspoken rules religiously. But.
You can reduce the impact of everything Facebook does.
- Acquire fans at a faster rate.
- Post less. Much less.
- More video, images
- Your post images are not attractive enough for Facebook.
- Your headlines are not catchy enough.
- Your stories are not unique enough. Let me explain. Most stories you have appeal to a fraction of your audience (and the rest will ignore them.) Widest possible appeal for your fans. Give them a reason other than “here is good information” to click. Give them stories they feel good about sharing.
We face the same problems you face, but at a much lower level. And we are confident we can tweak these parameters to stay afloat.
All the best!