Chris, your argument that the “Indieweb should stay with WordPress because that is where the users are,” is valid. I’d not really considered that but it makes sense. Also, I’m more confident that Known offers something close to what I suggested. That was not true when I wrote the orginal post. I ended up finding more detailed information on Known on the Indieweb wiki Known page, than I did on the Withknown site, which is odd if you think about it.
I think we will just have to wait and see if WordPress 5.0 and later can remain a viable Indieweb platform. As you pointed out the team of volunteers dealing with the WordPress side are doing an impressive job despite the adversities so if anyone can pull it off they can. So with that, and some better knowledge about what’s going on with Known, Pause I am somewhat reassured.