I really think they need to thank President Trump for that. He saved Twitter.
I don't know if Trump is really causing Twitter usage to increase, but it has certainly made people who don't use Twitter more aware of it.
If you compare the awareness/user ratio on the various social media platforms, I bet Twitter's is pretty high, which means they have potential for significant growth if they can improve the UX and the "how do I use Twitter? Why would anyone use it?" problem.
I remember following Scott Adams, whose work I enjoyed. Before he started talking about Trump, he had some 40k followers.
Since Trump, his follower count has ballooned to 250k and he almost exclusively talks about Trump now