And of course, all of us being open-source people, we do try to support those hardware components even if they are no longer officially supported. Daniel Vetter for example still uses his i810-based card, and is able to work with it without much problems (well.. as long as hardware permits) today. Even in 1920x1080 mode for example - it still works .
But in general, the problem is that this process is extremely time and resource-consuming. So our team's goal is to stay focused on hardware enablement in new kernels and userspace components, which are more critical and need much more attention to be working. So we leave the backporting and support for historic (by historic I mean 'no longer manufactured nor supported by any major customer') hardware to the downstream (in this case, Linux distributions or OEM/ODM companies who provide such hardware). So for such kind of support, asking Intel OTC team directly won't help much, as we work primarily on latest versions of the projects (kernel, mesa, and so on); and with each Intel Linux Graphics stack release we announce which hardware configurations it was tested with and with which ones we guarantee it to work. The best way would be to contact the OEMs or distribution support channels, so they could escalate this via proper support channels and provide us resources needed for such support.