Theory: network analysts at Twitter have identified exactly this - all highly central nodes are disproportionately migrating to Mastodon, hence the mastodon profile link ban.

Those who Tweet 'professionally' ie. tweeting is a big part of how they generate income, have every reason to worry about Twitter collapsing, and to make sure they are early adopters of whatever appears next - so they are unusually likely to at least hedge their bets with a Mastodon profile. These same individuals are likely to have high centrality in the network.