I think it’s quite likely that Twitter’s audience will fragment across several venues: Mastodon, Threads, Reddit, The Fediverse, Telegram… depending on their proclivities. Just the journos are hanging on to Twitter for some reason that escapes me. Honestly, Twitter is a zombie company now with probably less than 1,000 people
working there (last reports in May, 2023).
If the advertisers don’t put it out of business, or the banks, then it’ll probably be the lawsuits from debtors (including severance claims, unpaid rents, … other contractual obligations that Musk can’t weasel his way out of).