nVidia dropped support for their minimal nv driver in the wake of their GTX 480/470 launch. I supposed nVidia believes they're back in the game and will no longer need to support the open source community. Not that they were helping much anyway.
With nouveau finally mature enough to outdo nv despite the fact it's not feature complete, nVidia can now rely on the open source community to support itself while it gives focus to beating AMD/ATI once more. This is a big mistake.
With AMD releasing specifications on their cards, it's only a matter of time before the open source driver catches up to their proprietary counterparts and AMD will be able to provide a user experience equal to that on Windows for all but their latest hardware essentially for free. nVidia looks to have underestimated the power of open source.
By not providing hardware information driver programmers need, nVidia is merely ensuring that their GPUs will have poorer support on Linux than AMD's sooner rather than later. For features present in both open and closed drivers, open source drivers are typically superior to their proprietary equivalents. Open source support for Radeon hardware will outpace nVidia simply because the nouveau developers need to spend more time reverse engineering nVidia hardware.