If you read between the lines, the reason they have tried and failed to implement this is fragmentation of the market. While more modern devices would likely support GPU usage, the older devices (or even new low end devices?) would not. So they either have to live with the current fragmentation or fragment the market even more.

Fragmentation is, of course, a huge point for Android detractors. This is a very real manifestation of that which shows that Android may stagnate in the future due to the inability to develop features for a significant number of devices.

However, for the most part, Android as it sits today has a low level of fragmentation compared to what could happen. I recently developed an Android app for 1.6-2.2 and only had a couple fragmentation issues (performance related and contacts API). Google and its partners really need to take a long look at the direction of Android and resolve the fragmentation now while its possible.