Thank you for pointing this out! As a scientist, I think you are definitively right with the point sources. We don't need a discussion about this, because it is a fact, especially for posts about novel literature or special topics.
I can only say it for my little series (I don't know if you read it or even talk about it among others) but I think that long posts are not necessarily bad or bad in general. To explain some topics you can either presume some basics or you extend the scope. I think, it is depending from the audience you wish to reach.
I asked myself severel times, if I should add some sources but in fact, I write about rather basic things and most time out of my mind. Maybe I could cite Wikipedia articles (even if this is not necessarily a reliable source) or my lecture scripts or general books. Until now, I decided against it because somehow I think, for scientist it is basic knowledge. And the audience I write for at the moment, would not use the further sources. Maybe I can add something like "for further information, you can read here and here". I will think about it. Maybe you or someone else has any suggestions?
If I don't use specific sources, I like to add an "read more about this topic here" section. That's often enough to make the post more credible, especially when it's just the basics.
Always remember: what's basic knowledge for you might be completely unknown for someone else.
Concerning long posts I recommend splitting them up in several parts, that's usually easier to digest for the reader.
Of course, the 1000 words maximum is just a suggestion. Not everyone will stop reading at this point but shorter posts attract a wider audience.