Well this is officially the GT5 wheel. Perhaps, there was an issue with S2U possibly being a better game and PD got mad and told Thrustmaster that full support for that wheel will indeed breech the contract.
So there we have it.
You're really fishing in the deep waters there
T500RS is the extremely different wheel than any other wheel currently on the market.
It's force feedback system software libraries and overall unique SDK have to be separately programmed into game, in way that is different from TouchSense HID technology that Logitech and other companies have been licensing from Immersion Software solutions from more than a decade now.
Current lack of support for T500RS - not just in Shift 2, but in all other driving games on PS3, except GT5 - will probably be solved by time, because no developer wants to alienate their userbase. And no hardware-manufacturer wants to have unhappy customers.
Also notice that T500RS is not "just" GT5 official wheel - at this point, it is the also official PS3 wheel that incorporates all PS3 XMB capabilities and such.
Since even PC drivers for T500RS were published approx. 1 month after release, it is very noticeable that actual implementation of HEART technology in software needs some time. Libraries for TouchSense/Immersion are around for a decade - and even Fanatec uses some kind of emulation of both in order to make itself PC/PS3 compatible (also notice how GT2/PWTS are using different kind of Microsoft-licensed SDK for X360 support).
In short, when developers develop support for T500RS, it will be supported. It is only matter of their commitment to support some technology, not the other way around.