Granted, I know very little about this, but I wonder if you could wipe the slate above the link layer for a "new protocol".

Devices all have bluetooth chips already, which is probably the hardest part of adoption.

Then you can define a new system on top, and even swap out the bottom if this new "red tooth" catches on.

Ofc you still have a massive uphill battle, particularly getting manufacturers to agree to a more sane spec than what we have currently (which I wouldn't hold my breath on, that's for sure)