I went back to page one of the thread that you linked to and the thread started out as a joke (and it should probably end that way).
The OP posted a photo of an ME sign that has a typo reading "Bay Lake Towers" (plural) instead of Bay Lake Tower (singular). From that, the OP (jokingly) extrapolated that there must be another Tower coming soon
The rumor of tearing down the SGW to replace it with another DVC Tower has been around since news of BLT being built surfaced. It does reason that if Disney would tear down one GW to build a more profitable resort, then why shouldn't it tear down the SGW, too?
No one can predict what course of action Disney will take in the future in order to increase profits. DVC is very profitable for them and it seems that is the direction that WDW Resorts is taking by only building DVC resorts for many years.
As far as the CR being "more heavily discounted," I just don't believe it. Public and pin code discounts are never only for one resort, they're usually for a broad range of resorts. The CR is a convention resort and frequently the Tower is booked many months in advance and the SGW books quickly because it's the least expensive monorail resort and the rooms are identical to the Tower rooms. When resort rates are raised every year, the CR's rates increase at the same rate as other resorts; they aren't "discounted" more or go up less.
I don't know what the CR's occupancy rates are compared with the other Deluxes (Disney won't make these figures public), but unless you actually know this, you're just guessing that it's "less popular than the other resorts".
I would be interested in reading csaribay's take on all this