For sure. That's an interesting theory I'd like to see more support for/against it. Let me play devil's advocate. Ghost Train, regarded as a winner here and by The Brick Show but can still be attained at MSRP. Some people backed Vampyre Hearse too, as best set of 2012, which I can still find on shelf, dusty from 2012. Yet some of the other Monster Fighters have doubled or more.
The Ghost Train. 4-5 pages before retirement. http://community.brickpicker.com/topic/1368-9467-the-ghost-train/
The Malevolence. 5 pages before retirement. http://community.brickpicker.com/topic/2170-9515-malevolence/
In hindsight, generally the Lone Ranger stuff seemed like a bad idea but during the time there was some optimism and balanced threads. You'd think at least the train would do well, but alas.
On the flip side, 60 pages and being the #1 most hoarded set hasn't stopped R2-D2 from doubling in price in less than a year.
Then there's Jabba Palace, Jabba Sail Barge, what happened? Discounts, availability, the actual set and who it markets to, etc.
I guess post count/activity could be used as one of so many valuable variables and unknown variables, but the weight alone seems so minor due to its unpredictability, or it needs to be better defined to be reliable only under certain circumstances (when other variables are present/not present).
Your turn valenciaeric!