I “feel” like one of the main issues with foss tools like Lemmy and Mastadon is lack of an advertising budget.
Going to throw a wild guess out there without a lot of supporting data, but I suspect Bluesky has a decent budget for influencers and that’s driving the traffic too.
Just a thought. I’ve been sitting here wondering why most people have not jumped and Lemmy and Mastadon yet. I personally don’t find either platform hard to use or confusing.