There must be some connection in between the fact how Thrustmaster is the only wheel manufacturer so far that has officially signed the Official PS4 Licensee deal with Sony and fact how their wheels are still the only wheels that are discussed as having PS4 support.
One thing stood out in my backhead, so I cheked the (my own) OP to realize how one "small" thing changed in the meantime without many noticed: 10 months ago, the semi-official and official wording was how particular USB wheels will work on PS4 if fhe developers will code the support in their games.
Few months ago the "condition" suddenly changed, and we start to hear how wheels will work if the wheel manufacturers supply the developers with the PS4 SDK.
Which is really a significant difference.
I have no sources to back up my claim but previous events and such change - together with the aformentioned THS licensing deal - probably really have to do with double licensing of some kind: first, the licensing from the manufacturer's side to the SDK/API holder, AKA Immersion Co. (Logitech being absolute #1 contender with their crazy share in market of already sold wheels, probably close to 90%) where I see the potential issue regarding PS4 as the new platform. Immersion can easily see how previous settlement with Sony for PS2/PS3 does not cover PS4, and they want their patent/license share. Which is two-level issue:
1. In 2007 Sony paid +$200 million for TouchSense patents compensations for DS2 and DS3 controllers, with Logitech wheels (official PS2/PS3 wheels of that era) being covered with the compensation. After that anyone can understand how Sony maybe decided to nullify themselves out of the such deals, with pulling out from licensing psrticular SDK/API as the platform holder for crazy amounts of money; and
2. While the main licensee of such deal - Logitech - is simply killed its own wheel division (check OP for linked details) in 2010/2011 and have no plans in renewing that particular division. So, Logitech simply have no business interest in licensing either Imerssion for TouchSense to be used on PS4 (they will not produce any PS4 wheel and why would they license for the wheels they've sold already?), nor they have any interest to license PS4 as a console (as Thrustmaster did) for the same reason.
And 2a. Also, the idea how "game developers" should see will they develop their game around particular support is no-go, since it would mean how particular developer should pay for such licenses - which I really do not see happening from the cost-perspective.
Another issue is the same problem we (as the owners of the wheels) recently had with the whole Microsoft (or)deal regarding support for the "legacy" wheels. Once we bought out wheels, we will not buy new ones. If Microsoft allowed us to use our legacy Fanatecs on XboxOne, Thrustmaster (and petty MadCatz, god bless their poor souls) coulnd't sold their new models to the main target-audience: people that actually want to play with the wheels. Because they already bought them. For a high price.
With changes in approach by Sony it seems to me how such complexion could be in works at SCE. Maybe they simply don't want to accept the fact they need to pay to Immersion for licensing the products from manufacturer that is not SCE licensee anymore and they've practically allready paid for twice before (in examples of the Logitech DFP and G25 models who are around since 2004/2005, be blessed forever, in both PS2 and PS3 era). Logitech have no interest to pay and - here we are. Nowhere.
I can see why THR went into deal with SCE. They have their own SDK/API, they are free of Immersion patents (which is a plus for Sony as well, since there is no middle-licenseer) and they are infact, a both PlayStation and Gran Turismo official product since 2010 (T500RS is the only official GT wheel since GT5 and also the only FFB wheel that have PS button since Logitech DFGT which was discountinued forever in 2011).
I would love to see some postive development - as I am the proud and happy owner of G25, CSRE and CSW - but all of these complexities give me a little hope at this point.