It might be my personal preference, but i find conversations on mastodon hard to follow once there are more than a handful replies.

Lemmy (or reddit) keeps the flow of comments well ordered and perfectly readable.

Don't know man. I have a pretty robust Pixelfed follow/followers lists. I regularly get more likes on PixelFed than IG, I think it's because my friends don't get to see my post due to the algorithm. PixelFed's chronological feed is better, imo.

Pixelfed isn't empty. Where are you using it?

Mastodon has a supermajority of users and traffic, and Pixelfed works seemlessly with Mastodon, which is why it's a focus. Twitter and Instagram are the normie platforms, and Fake Twitter + Fake Instagram is something that they would find appealing if the embedded Mastodon userbase wasn't littered with actors hostile to Twitter and Instagram users taking over the space.

Pixelfed is definitely not empty. It even includes posts which include images from Mastodon. I actually find it the best part of the Fediverse, with absolutely loads of great photography and art. Just try following a few hashtags that you're interested and see 👍

I think it's because instagram, youtube, and facebook are way bigger than reddit, so people coming from them are less likely to go to lemmy.

But the way the fediverse works means they are useful even if they aren't that popular yet. People can follow peertube accounts from mastodon or lemmy. I follow tons of mastodon accounts from my pixelfed acccount. And friendica can handle almost any type of content.