Because Blu-Ray won the format war, why can't they buy the technology of HD-DVD?

This would help everyone out so much that have purchased HD-DVDs. We hear of combo players that can play both HD-DVD and Blu-Ray Discs, but those are pretty much discontinued. If Blu-Ray is able to get/buy the technology to add in the capability of playing HD-DVD discs as well as their current technology, it seems everyone would be saved. Right now the hundreds of thousands of consumers that have bought HD-DVDs need to keep their whole HD-DVD player in order to just play the few HD-DVD's.