Depends.

Lemmy and reddit are definitely more media friendly.

I think reddit managed to capture a certain generation of users for a lot of topics, and I think its recommendation algorithm helps keep the user experience more interesting by throwing exposing the user to new groups they may be interested in. Very similar to how YouTube works.

But like other social media, the reddit algorithm also creates a very silo-ed, radicalized user base.

Forum users tend to be older, and I have seen a few specialty forums die off due to attrition and a lack of new users.

I think one huge benefit of forums is the good ones are tightly moderated, so bots and trolls are quickly dealt with.

Forums whose topics where age is a lesser factor, or where non-commercialization benefits their userbase, are lasting longer, but generally they're getting picked off.

I think Discord is more like a media-friendly IRC, which was never my bag so I'll let others opine on it.