Thanks one and all for the responses. My take-aways from this thread:
At the end of the day, a true benchmark for $/SCV remains elusive. Many of you have reiterated the truism that catalog values are not an indicator of purchase price. No argument from me. Agreed that traditional brick and mortal establishments are a non-existent choice for many customers – making the discussion irrelevant to some… but not to all. In place of brick-n-mortar, my query should have posited
face-to-face purchases (broadened to include bourses, shows, etc.)
Regarding statistical estimation: I still believe it's do-able, to a point. All admonitions about the disconnect between market and SCV are noted. However, one "bad yardstick" used repeatedly by many people is better than no yardstick at all; at least the distortion is applied consistently. For those of you who accept that, then (theoretically) there are two statistical approaches: (1) comparison of the average $/SCV for online transactions vs the same for face-to-face transactions, and (2) multivariate regression analysis of all transactions where the dependent variable ($/SCV) is a function of a number of independent variables, beginning with condition and grade; one could go to town with additional variables for type of venue, geography, and any number of buyer and seller characteristics. However, the effort required to amass such data is prohibitive. It requires many people to collect data, and each would make his/her own subjective measurement – so then, "garbage-in-garbage-out" becomes an issue. This pretty much bars the multivariate regression option. So the first alternative (comparison of two averages) emerges as the "better" of the two approaches, warts and all. Someone with a lot of time on their hands COULD pursue this via
ebay.
Having said that, a couple of responses here gave fuzzy approximations of what I was looking for.
Hal suggested that a $/SCV ratio of 61% was "excellent" for a brick-and-mortar purchase. This is a nominal (non-quantitative) measure, and better than nothing. Similarly,
StateRevs indicated willingness to sell me any number of varieties at 50% of SCV. I got a good laugh from that. Still not a definitive quantitative measure, but another nominal metric.
Moving on now to the qualitative side…
There were some very thoughtful replies that reiterated the value of buyer-seller relationships sustained over time. For the most part,
ebay engenders what I call "drive-by" transactions. I risk stating the obvious that this approach can be useful in some situations, but so too are the benefits of the ongoing relationship. A balanced diet is a strategic mix of the two.
Pursuant to the last point, I visited yesterday a brick-and-mortar store for the first time in decades. The whole experience was quite enjoyable. I intend to make regular, repeat visits.
Finally – I am reminded again that precise word choices are critical in an online forum. Here, we do not have the ability to clarify in real time as we would if speaking face-to-face. I dropped the ball in that regard, beginning with the title. It suggests that I was seeking an evaluation of one specific transaction. I had to add a couple of follow-up posts to make myself clear. Sorry about that, folks. Overall, I found this discussion quite useful.