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Hero
If D&D doesn't allow third party publishing, it forces the 3rd party publishers to compete with D&D, using the Pathfinder system. Or whatever, but mainly Pathfinder. They have the choice of recruiting a mass of competitive allies, or throwing all that capital and creativity onto Paizo's side of the scale. It's an existential decision. Not this year certainly, but as early as next year I think the absence or presence of third party publishers will begin determining the ultimate survival of D&D in the face of Pathfinder.
I think you're on base with the comment (not quoted here) that "the rest of the WotC business model has yet to roll out". The first products we know of are clearly (to me) being done on a freelance studio basis. I expect that this will probably continue to some degree. However, it also frees up manpower at WotC. WotC and TSR are no strangers to freelancing, but insofar as I know, it's primarily done on an individual basis, and at some point gets brought in-house for editing. Hire a studio, and you get editors as well. It still need an official overview, but less official resources overall.
I doubt WotC's plan is to keep two people on to read the freelancers' work and rubberstamp it. The references in the PHB to WotC settings strongly suggest that those mentioned will not be licensed out; they might be done in house, or they might be hired out to a studio to develop a few books, but it won't be a license deal. WotC will capitalize on those properties, however.
WotC isn't going to suddenly put everything under the OGL, either. Will there be a public license? Almost certainly. I expect some kind of OGL/GSL hybrid, but we'll see. I'd bet that this isn't a settled issue at WotC, either - more likely it's temporarily tabled as different sides see how the public & 3PP react to an unlicensed D&D, and they'll come back to it at the end of the year. I fully expect restrictions on content; I've posted a number of ideas about this before, but put bluntly, a replacement Players Handbook isn't going to be easy. WotC wants 3PP to support the smaller parts of the game, not replace it wholesale. More races, classes, add-on rule sets, that stuff will be good.