It's contextual. Perhaps the biggest exception to your first stip., is that if you are writing niche blog posts for that particular audience, then you will generate popularity and viewers based on how well you get into analysis of the field and are rewarded for being detail oriented, but this is primarily focusing on content and not so much length.
Take for instance Paul Campos's Blog:
Inside the Law School Scam, in which a dean of Law School at Colorado Boulder shares his dissenting opinion on the admissions process of his profession. Professor Campus has many posts filled with quantitative numbers for employment analysis and his reader comments do not show any variation scheme based on relative blog post length.
It is possible that this popularity could apply to Teran's exception, that people love drama filled callouts, the idea of a law dean bashing the process of accepting students sounds like an entertaining contradiction that puts him at odds with his own job. However, even though I believe this factors into it, I also believe that high quality content will get popular if the appropriate audience is aware of it.
Blogs themselves are a dime a dozen and unlike smashboards, there is no general population already there to read whatever you have to write. In the case of sources being in plethora ie blogs on their own, it depends if you are able to get a target audience and often times this is achieved by writing in niche and providing detailed commentary that people wouldn't get from someone else perhaps writing about the same genre.
Professor Campos has his hook, he is a professor discussing problems with law school and gives us an "insider" perspective on the genre he writes about which is the law school admissions process. The line is his use of data and research to uncover faulty employment statistics and fraudulent polling methods and the sinker is that his ultimate message is for students not to go unless they are willing to gamble $120,000 for a 70% shot at winding up unemployed.
