With Twitter automation, I think it's an understatement to say that following count is not a reliable measure of influence. Your two subjects here have real world influence, and it's reasonable that they could arrive at those huge following #'s without gaming Twitter.

But I've noticed that certain popular tech news blogs (for example) - every single time they have a post, there are hundreds of Twitter accounts that retweet the content, instantaneously. And of those accounts, they ONLY tweet that outlet's content. I think investigating those most popular tech blogs' average "what happens when they post an article" via this type of Jaccard index would be an interesting exercise in exposing some tomfoolery, and enlightening in seeing how much stuff is being gamed. Knowing what we know about human nature, is there any doubt that people are going to great lengths to juice their follower counts and game the appearance of getting "engagement?"

The threads being pulled in this post have really interesting implications for type of analysis of "what's really going on" both in terms of a Twitter profile's following, and the authenticity of the "sharing" that occurs among their followers when they post something.