I can't recall any other OSS project that makes so much money and has nothing to do with infra/cloud.
They were making around $1M a year back when they complained about the revenue. A lot of Linux distros can only dream about such an amount of money.
They had a very good run for such a project.
[1] - https://adamwathan.me/tailwindcss-from-side-project-byproduc...