I have found < 2% "engagement" to be more or less average, even for accounts with 20K+ followers.

I personally think posting long form content to Facebook or Twitter will result in fewer people seeing the content, than if it were just on a blog, as it will probably receive a similar level of engagement as a Tweet or short post.

Social Media is great for listening but it's not great for getting the message out as such a small percentage of the people we're connected to actually see what we post.

I've found blog content tends to receive ongoing views, over the long term, without spending additional time promoting it. Social Media posts, even if they are not auto-deleted, tend to be more ephemeral.