The answer probably is, it can't. There's no incentive for that guy to leave Twitter. There's more of an incentive that someone already on nostr or a nostr newcomer comes here and starts developing a following. They'll probably never get any attention on Twitter because they are small fish in a small pond. Here, they might get some traction.
Discussion
I do wonder if that’s the answer, that it simply can’t compete in the same way. Maybe it doesn’t need to, though. The creator incentives on platforms like X are designed around them generating advertising revenue for the platform via engagement with their followers. Nostr is a different paradigm.