TailwindUI isn't really what I'd consider SaaS -- it was a buy once and download software product.

That means to keep making money they need keep selling new people. According to them, their only marketing channel was the Tailwind docs, AI made it so not nearly as many people needed to visit the tailwind docs.

If they had gone with the subscription SaaS model, they'd probably be a little better off, as they would have still had revenue coming in from their existing users.