Web of trust. I saw him followed by a lot of other high rep npubs early on. But I can't prove it, you've got me. I'm surprised he's not on nostr.directory
Discussion
That account was one of the earliest on here. I think it was there when I signed up in December. But never seen any verification messages on known saylor accounts (e.g. Twitter). It could be him, but it could also be someone who set it up knowing it would get a few follows from high rep npubs and create the snowball. No idea.