Tailwind UI is still in preview with very few components. There's no way it generated 2 millions. No even 10k. This is a gross publicity stunt.
As a developer, Tailwind UI is a god send, I've been waiting for years for a great looking CSS framework with pre-made components
(Also, they had a pretty big audience already after selling Refactoring UI which is a really useful book for developers that can't design, like me)