Just for reference, there have been several other prior proposals to solve a similar problem that have attracted significant discussion, with the most extensive and developed (besides the one you mention above) being this one:
ISTM that there is a lot of interest from users and no major show-stopping objections, but the main blocker has just been there are a lot of tricky details, behaviors and specific interactions to work out, and thus far the discussion hasn’t gotten enough of a critical-mass consensus on these issues to motivate someone to write and propose at least a pre-PEP, which would be the presumed next step.