After whining about "useless google takeout", I decided to do something about it. Initially, I contacted Wordpress to see if they were planning to do anything and/or if they already had a plugin or script. It turns out they don't. I think this is a missed business opportunity. Everyone just seems to abandon their data when switching networks. I don't think that's a smart or realistic thing to do. So, migrate it. The Internet Archive and ArchiveTeam are trying to save Google+ content as well.
I started to parse the XML files in the Google Takeout results for Google+. It took more time than I expected, and then started to work with a talented person named Nicholas. The goal was to take each public post on Google+ and turn it into a Wordpress post, with title, hashtags, categories, images, and geolocation all intact. It's a tall order because mapping and migrating between social networks is never easy.
He re-wrote everything I did and while it's still a bit rough, it does work. The code is hosted on my code site. Basically, you run these scripts from inside the directory of google takeout. Nicholas is setting up a service to do this as well. In theory, you'll just do the Google Takeout for your Google+ posts and then import the resulting XML file into Wordpress twice. Yes, twice. For some reason, Wordpress doesn't catch everything on the first import, so doing it twice makes sure all of the content and attributes are imported correctly.
I was the first user. It works. I've successfully imported and published all 284 Google+ posts from the past 5 years. They aren't specifically tagged as Google+, but they are available in my Article Archives.
For those inclined, the code is available and you can convert away. Nicholas is also available for hire at https://www.upwork.com/o/profiles/users/_~015da32eeb3c21dc5b.