What you’re saying was not clear from the start, you keep moving the goalpost.

Ironically XML allowed namespaces so css:color="red" could have totally been a thing. However CSS came out to separate content from style, so doing that wouldn’t have made much sense. I wouldn’t be surprised if the style attribute was added later.

Edit: wow I was right:

> HTML 3.0 supports style sheets via the use of the LINK element [1]

> HTML 4.0 adds new hooks for style sheets, which suggest how a document is presented. The new ID, CLASS, and STYLE attributes [2]

[1]: https://www.w3.org/MarkUp/html3/intro.html

[2]: https://www2.cs.sfu.ca/~ggbaker/reference/wdghtml401/new.htm...