I very much agree with your observation that the involvement from hardware vendors was minimal. It definitely would have been advantageous to slow down, and it's beyond disappointing that it wasn't pursued further. They absolutely dropped the ball in that regard.
AV1, however, is first and foremost a video format. A very popular one at that. It's perfect for video, and that explains the great industry support. The fact it is the most promising option for video is why it's seen hardware vendor support, not because AVIF is ideal. JPEG XL unfortunately doesn't have this luxury, but still could have done better. This doesn't mean that JPEG XL can't see support now, though, and there are plenty of opportunities for hardware support now it's been proven viable.
While there are certainly employees at Google that have contributed to JPEG XL recently, I'm still yet to see any evidence that the company itself has provided any direct support lately.
AV1, however, is first and foremost a video format. A very popular one at that. It's perfect for video, and that explains the great industry support. The fact it is the most promising option for video is why it's seen hardware vendor support, not because AVIF is ideal. JPEG XL unfortunately doesn't have this luxury, but still could have done better. This doesn't mean that JPEG XL can't see support now, though, and there are plenty of opportunities for hardware support now it's been proven viable.
While there are certainly employees at Google that have contributed to JPEG XL recently, I'm still yet to see any evidence that the company itself has provided any direct support lately.