A lot of open source projects attempt to become a business in some form or another (or vice versa). Great examples of this include Astral (creators of UV and Ruff), TursoDB, TigerBeetle, etc etc etc. People want to get paid for the project they work on. Some of their business models will fail. This is probably a case of tailwind growing their engineering team faster than they should have when the AI writing was on the wall in 2023.
I think a problem is that tailwind has no moat compared to most of those. If it never received any further updates today it would still be effectively feature-complete, save for the occasional new css features.