"the cost and durability has been a serious issue."
That's probably where the idea died.
A community to ask questions of the form "Whatever happened to ... ?"
"the cost and durability has been a serious issue."
That's probably where the idea died.
Maybe this question didn't have the right answer:
The biggest remaining question is over durability, and answering it will require spending some time to do accelerated testing by running the material through repeated hot-cold cycles.