I agree it would be great to get some of the vendor pushed / common domains put into an accepted standard.

In my interaction with IETF standards they are created / implemented in two ways:

  1. They set the forward direction for a new technology before it is wide spread.
  2. They wait for a technology to become popular / accepted and start to set standards from that baseline.

Both are reasonable paths of implementation given how the pace of changes in technology.

I doubt .lan, .local, .home, etc will either become public or a standard just based on existing devices that default to these domains and documentation or books that might reference them as example domains.