I think in part it's that a few Lemmy communities are extremely active / almost spammy and there's no algorithm filtering how much content you get from each place. In the "All" view, most of the content I see comes from the same couple of Lemmy "meme" communities. So it's no wonder most of the content I'm seeing comes from Lemmy when almost all of it comes from two specific communities which are basically meme factories. If I filter those out, there's suddenly a much bigger variety of content from all around and on my "Subscribed" tab I can see plenty of activity from Kbin communities.
Why does it seem everything on KBin is from lemmy? (kbin.social)
I want to check out KBin, but it literally the whole 1st page, the top 25 posts, were all from Lemmy communities....