It will only die if Musk shuts it down or something else becomes more popular at delivering the same function. Twitter is different from facebook and the pic/vid social media because it's primarily text driven, tweets are primarily public and it allows an open exchange between the common folk and voices with more social influence (e.g. businesses, celebrities, experts). Is Mastodon or any of the other twitter-like sites doing something better to drive people to move? Toxicity on twitter might help move people but it won't kill it.
If you look at myspace vs. facebook, facebook won for a few reasons. When it started you had to have a college email which basically kept it to a young crowd. Facebook is kind of like myspace (friends, wall) but it seemed safer because you couldn't be anonymous. That was a huge reason why facebook was considered a more credible platform than myspace. The big thing it did better than myspace or other earlier platforms was to blend your friends' posts into your wall as a single stream of content you could engage and you could engage in other people's content. Facebook officially killed myspace when it opened to everybody.
Compare that to snapchat, which has been nearly wiped out by instagram adopting the short lived story format into a larger platform with more functions and most snapchat users were already on instagram, too. New doesn't always beat old.
