I know exactly what you mean.
At first, for my current series expose, I thought I could fit it all in one post. But as I was typing it, I got to the beginning of the second part (the CDC) and the system told my I had already exceeded the allowable word count. Hence, I knew thenceforth I would have to segregate it into many parts.
Even in Part 6 on the Rockefellers (my longest part), I had to split it in two! LOL
I think we opt for lengthy instead of brevity because we want to make sure that everything we know of is exposed (and recorded for posterity) even though we risk losing eyeballs that have better things to do.
Bad habits die hard?