But still it is not reddit before reddit api changes.
Nor Mastodon is Twitter in any moment of Twitter's recent history.
Anyway. Regarding your post: it seems to me that the hashtag+short reply system is simply more popular than the community+long reply system. Even then, when compared with the platforms that it competes with, Lemmy's popularity is proportional to the one of Mastodon and other Twitter alternatives.
However Mastodon is MUCH easier to use and has better pull as you follow people.. If a person was on Twitter and moves to Mastodon you setup a Mastodon and follow them.
However for Lemmy, if you liked a specific subreddit and not everyone left you search for an equivalent and you find 6 plus (IF your instance is federated with a few even for the search to return results) then you try them out and find little interaction in some etc.
TL;DR following people is easier than creating communities that are active.
Actually I'd say it's the other way around. It's hard to switch a social network, since it only makes sense to switch if the people you want to follow are also on the new network (The Network Effect).
However, for sites like reddit, it matters less. I don't care who posts the cute kittens in !aww@lemmy.world, as long as they're there. Much lower barrier to join. Once a network is primed with good content, the people will come.
More inline with OP: it also helps that there was already a huge exodus from twitter to mastodon a few years back, so they've got a bit of a head start.
I would argue normies follow people to new networks. People don't go seeking out content on lemmy.. If you google search stuff you end up with redit content hits not lemmy content hits for nearly every topic.
To move off Twitter, one person will potentially bring hundreds.
To move to Lemmy you need a bunch of people posting useful content..
Auto posting content without discussion also doesn't seem to stick.. I was looking at Lemmit which is mostly bots reposting reddit stuff and there is 0 discussion there.
Because Eugen has been working on Mastodon much longer. It's a lot more mature and it had time to get a bunch of real world testing, not to mention withstand some DOS attacks, some hateful trolls, etc etc.
So pretty much every aspect was more mature and easier to use when people started jumping to the lifeboats from Twitter. Lemmy is cool and it's getting there, but it's got a ways to go for sure. (The lack of RES hotkeys to navigate, vote, open and close pics, follow links, jump between all and subscribed is purely torture to me at this point!)
@niszogen IDK if I’d consider it just a Twitter alternative. From Mastodon I can follow any Lemmy communities on federated servers and see the same posts that I can see in my WefWef app on my @Khazram@lemmy.world account.
@niszogen All I have to do is know which instance, the community is that I want to follow, is on. For example @aww@lemmy.world was the first option that came up when I typed Aww into my Explore tab on Mastodon but I could also follow @aww@lemmy.ml if I wanted to.