I will stand by my statement. Seated Quarters seem to me to be the poster child for a series that even many of the common coins are hard to find. I wish I could remember the pundit and his exact words. He wrote something like "Morgan dollars are common coins pretending to be rare coins. Everyone knows this but nobody cares. They are big, shiny, can be collected a hundred different ways and there are plenty for everyone. Seated Dollars are true rare coins but nobody cares. The vast majority of collectors just hope to get one or two for their collection and there are a few semi-common dates that meet this need."
I think Seated Quarters have a similar relationship with Seated Half dollars. Seated Halves will never be Morgan's but they are big and shiny , can be collected a hundred different ways and except for a few dates there our plenty for everyone. Seated Quarters have numerous hard to find dates, some considered rare some considered common. There are also a few dates that are very common and much like Seated Dollars, these coins are the mirage that Seated Quarters are easy to find. The vast majority of collectors only want one or two for their set and these fill the need. It is when you try to dig a little deeper that you find (Or don't find) many Seated Quarters.
As far as the LCSS goes, I am a recent member. I also think the earlier members of this club play a role in the lack of Seated Quarters. I think the early members recognized the rarity of Seated Quarters in general and salted away many of the attractive, collector grade coins. Today's collectors are trying to make a meal out of the leftovers from the feast.
As far as personal experience goes, I know very few coin collectors personally but of the seven or eight collectors I know who collect Seated Coins all but one collect Half Dollars. My own collection features Seated Halves and building a date set was one of my favorite experiences.
Hate to digress, but I must tell you about collector number 8. He only collects Carson City Seated Dollars. It felt like he was taking me to see Jimmy Hoffa's body but it was worth it. Probably the only time in my life I got to see what could be termed a "Collection" of 1873-cc dollars. He has dozens of Carson Dollars; all raw. In fact at the time he had just purchased a PCGS F-12 1870-cc Dollar, and because he hates slabs he offered to sell it to me for $400. ME? ME! I turned him down because I was going to get a VF or better coin for my collection. I actually get physically sick every time I think I could be that stupid.