> Tailwind looks ugly, but there are no hidden abstractions or structures in the code

Verily, Tailwind is the assembly language of CSS. No structure, no semantics, no abstractions, only twiddling specific bits of visual representation.

To turn to it is to admit that your product lacks the structure and the design vision that allow to use some abstraction ("semantic classes"), and that all you can usually do is to patch some areas of it, disconnected from the rest, and unable to touch the rest (lest it goes down in flames). Assembly is definitely suitable for patching.

This is often the endgame of old large products that changed hands and directions many times, without much care.

This seems like a radical, unsupported conclusion to draw from a single frontend architecture decision.

Maybe there's an overwhelmingly positive case to be made for high-abstraction CSS with hidden structures. Outside those few select cases, we've known the tradeoffs for 25 years, and the added complexity is rarely worth it.