What is the issue with the HTML Standard?

If the video element offered loading="lazy" support, that attribute could be used to determine how other desirable video features behave, such as when autoplay starts playing, and when its poster image and video file data are fetched.

For example, loading=lazy combined with the autoplay attribute could cause a video to delay its poster image loading, its data fetching (other than metadata perhaps?), and its autoplay behavior until the video element is in (near) the viewport. Per my understanding, lazy autoplay is currently doable with JavaScript and it'd be great to offer a declarative HTML alternative.

Could <video loading="lazy" ..></video> be one already-familiar way to offer a set of lazy behaviors for video?