In Tumblr, you can “re-blog” and add your own content and even your own hashtags, but it still remains within the original thread.
If anyone leaves a comment to someone else's re-blog post, that comment is still part of the original thread.
If someone re-blogs your re-blog, same thing, still part of the original thread.
Tumblr's re-blog feature is both a “comment” in the original thread, and appears as a “quote-reply” under the account owner's profile (or blog in this case).
It seems to work, and maybe Tumblr's approach is the middle-ground for the debate in the #Fediverse?