[cletusw]

You have to differentiate between the WHATWG and the W3C, which have different goals/purposes and different HTML specs.

As the link you referenced states, the WHATWG's non-versioned living standard attempts to stay "a little ahead of the implementations" with the goal of (hopefully) guiding implementors toward common goals.

The W3C periodically looks at already-implemented features and creates versioned snapshots (like HTML5, HTML5.1, etc.) with the goal of providing developers with a stable, known set of features for development.

Different purposes, different specs, both useful.