I think part of the issue stems from Lemmy not having a good way of tracking a topic / community defined on multiple instances, so you have to track a community on each instance. People want the most active one, so they track the one on LW since it has the most members. And since they track mostly communities on LW it also makes sense to just use LW as the primary.
If Lemmy could have some inbuilt support for tags or subscribing to a topic / multi-instance community, I think people could feel less inclined of defaulting to the largest instance.
I understand the frustration, but I do believe this is a strength of Lemmy. Small; individual communities is what gives incentive to stay independent, and if you just want the broader content, that’s exactly where and why large instances like Lemmy World is also beneficial.