I'm a bit skeptical that #Twitter will die soon. A lot of people will stay because #Mastodon is not made for them or they have a large following community and they don't want to start over. But advertisers are gone so IMO Twitter will run out of money long before the user base quits
#RipTweeter
Also Advertisers can come back and running a Mastodon server is not free. Let's see how it plays out in the long term