OK, "reverence for authorities" might a red herring here. Please disregard that and accept a fractional apology; I think my observation still stands.

Robin's saying "the expected value of your reading (something like) a classic is higher than the expected value of equivalent time spent reading (something like) my blog".

He isn't saying "you need to read the classics (and nothing else will do)", in spite of what the title says. You sound as if you're reacting to the title only - and an idiosyncratic reading of it at that.

Your point regarding a specific article - Coase's - may have merit. Some issues you need to consider are:

• Reading a primary source often allows you to understand how it has been misunderstood; there is a (ahem) classic example in the field of software engineering, where for years the article cited as the primary inspiration for the well-known "waterfall lifecycle" was Winston Royce 1970; it turns out, when you actually read the article, that it condemns the waterfall cycle as oversimplistic and unworkable - here we have a misunderstanding with a cost measured in billions and attributable to failure to read the classics carefully.
• As a corollary, modern popularizations of a classic may contain distortions due to the popularizer's various other biases, including poor skill at explaining; just as much as they may enhance the value of the classic by providing a streamlined explanation; how are you to sort one from the other?
• A distilled explanation of the insight from a classic strips it of all the anecdotes and background material which lent the insight force in the first place; that may be valuable and, depending on your purpose, even more valuable than reading the primary source, but it doesn't convey the same understanding; your grasp on why the insight has force may be shakier than if you'd read the primary source. There's often a trade-off between time spent acquiring an insight and depth of understanding. (Admittedly, this trade-off can be substantially modified by the time you spent exercising the insight.)

Another respondent on Robin's blog says "Pfui, blogs have led me to classics". Well, that point doesn't work if all you ever read are blogs, showing precisely how I suspect folks are misunderstanding Robin's point.

What Robin says is that there is a hierarchy of sources of knowledge, not all are worth the same, and it's unwise to spend all your time on secondary or tertiary (etc.) sources that (often) are lesser sources of intellectual nourishment. In short, there's a reason the classics are acknowledged as such.