One of the things that could really help here is to create a license along the lines of "GPL for hardware" and then for a company like Google or Meta to release a design under it. The design wouldn't even have to be state of the art; something with performance equivalent to a ten year old x64 design would be valuable enough that people would use it for things if it was free.
But the larger value is that then people could use it as a starting point for modifications, which would in turn have to be released under the same license. Soon you have a diverse set of designs to choose from and we can start getting open hardware into common use because using any of those designs would be a cost savings over buying or designing something equivalent, but because the license requires an open design the user can then create custom firmware etc. and we might finally start to do something about the IoT security nightmare.
But the larger value is that then people could use it as a starting point for modifications, which would in turn have to be released under the same license. Soon you have a diverse set of designs to choose from and we can start getting open hardware into common use because using any of those designs would be a cost savings over buying or designing something equivalent, but because the license requires an open design the user can then create custom firmware etc. and we might finally start to do something about the IoT security nightmare.