I'm not seeing a similar domino effect in the US yet, but the complete eXit of the Trevor Project (not active here yet) and the partial eXit of @indivisibleteam could set the stage for more large accounts to follow.
As the Trevor Project noted, X is not a safe platform. Orgs posting on X risk exposing constituents to harm. By stack-ranking paying accounts above everyone else, Musk has worsened abusive behavior, because abusive accounts can pay to amplify their abuse in everyone's timelines.