Well, user traffic has returned to normal, but we also have to consider that it's just traffic. Some of that traffic is also a bunch of people talking about Reddit, protesting, etc.
That being said, I don't think Reddit will die from this, but it doesn't need to in order for the Fediverse to succeed. All it needs is to push enough people onto federated services and kickstart it, just like Twitter did with Mastodon. We aren't going to all switch overnight, it will be a gradual process.