I guess there are issues with the post formats, micro blog and forum styles are quite different, and there's probably a cultural friction between people who like community based pseudonymous forums and strongly personified social media.
Let's hope we can one day have a common share place for information with UIs adapted to every tastes.
I'm not following the proportion point, but about non-US on reddit, r/france has 2.1 M readers and r/de has 2.7 M readers. They are very active, it completely dwarves anything on Lemmy. Any national subject is going to be discussed there. I am not using those by activism, but I can't blame the average person to prefer those vastly more active places.
I think it's good to have them doing their own things, but it is just not big enough to be as entertaining and wide-covering as Reddit. j'ai.lu feels more like a forum with 50 active members that you would check once a week.
Would the partner remain strictly online too?