So if you want to buy something like Quincy ME, Kojak, Adam12, NYPD Blue, WKRP, etc .... at dump bin prices (ie. significantly less than $10 a pop), you'll have to either get very lucky or just wait until the Sony, Fox or Universal licensing contracts with ShoutFactory ends.
Judging by ShoutFactory's actions over the past 15+ years, I strongly suspect their MO is to keep their titles as quasi-evergreen and very little to no liquidation to dump bins. (ie. Before the licensing expires).
(Going further offtopic in regard to dallas).
To eliminate any ambiguity when talking about the Dallas seasons, the nomenclature I use explicitly is the "dream season" being season 8 / (season 9 DVD). The first 1978 episodes are explicity referred to as the miniseries / first five episodes...
I would be quite surprised if this ^ is what is going on.
There is one giant couterexample to your assertion: Northern Exposure (NE).
Universal released the first several seasons of NE on double-sided flipper dvd discs back in 2004-2006. Universal then re-released them again as single-sided...
Most likely Shout Factory already has a lot of past sales data to see whether there is a "good number of other customers" who didn't buy single seasons but who would be willing to buy complete series sets.
For example, shows like GI Joe, Transformers, The Bob Newhart Show, Hill Street Blues...
(More generally).
What are the primary reasons why a complete series set is even released in the first place ?
In the case of a tv show where every season was previously released individually, I would guess it is largely to clear out old inventory collecting dust in their warehouse. (ie...
Shout Factory seems to have very little to zero interest in releasing tv complete series dvd sets like this.
I was hoping for an NYPD Blue complete series dvd set, but it will likely never happen. (Shout Factory released seasons 5 to 12 of NYPD Blue, after Fox gave up on it after the first...