What I know is that recently I have been contacted by WordPress core developers about some details, and that the goal is to merge it at some point, but there is no timeline provided.
As both WooCommerce and Google Site Kit now have integrated with it, I think this will make it very likely that the project will move forward again, as the developers from these plugins are either from Automattic, or well connected.
The reason the status is currently closed is probably because at the beginning, nobody within the WP Core dev team really understood the purpose and necessity, so they closed it. But recent developments in WooCommerce and Google Site Kit show that the this is changing.
As there is no alternative to get this issue fixed in core, I’m confident it will land in core eventually.