Who are the accounts that can hurt Twitter the most? I'd argue it's not going to be celebrities unless the celebrities leave Twitter loudly and promise to engage more on a new platform.
I think Heather Cox Richardson, who engages daily and shares useful content AND has the largest substack following in the world (last I knew) would be a massive hit.
Who else? Orgs like CNN sure, but people?
@Calibabe that'd be a very very big hit to twitter. Good one.