With respect, I think you're confusing a one-sentence description of a planet in a world book, or even a two-paragraph description of same in an article in a Pathfinder AP volume with the sum total Paizo will ever do with the Red Planet, which would be a huge mistake.
We're in it for the long haul. Just because we make an off-hand reference to something once doesn't mean we're done talking about it, or that that one sentence conveys all the depth a given concept might get over the course of the campaign setting's life.
I also think you're guilty of a little hyperbole on the campaign setting issue in general, though I think a lot of your other observations are quite astute. To wit: There is a middle ground between doing "no setting," or a setting that is so light on detail that it might as well not exist, and doing six or seven concurrent campaign settings, all of which lack distinction from one another.
I don't know if the 1990s Dark Sun stole customers or sales dollars away from the Forgotten Realms, for example, but I have a hard time understanding why, from a business perspective, a company would concurrently support Greyhawk, the Forgotten Realms, Dragonlance, and Birthright. Those settings _do_ poach off customers from one another, and I think the profusion of mutually exclusive, superficially identical campaign settings was one of many elements that eventually led to the doom of TSR.
It's not an either/or proposition.
--Erik