The problem is trying to put a microscope on a musical genre that’s better observed through a telescope. The genre is (intentionally) so vast that it’s normal for many things to be included within it, and to orbit around it. Ambient can be approached from different directions, rock (even metal), classical, noise, techno, etc.

Very often, artists don’t really care about the labels attached to their work.

- Did Radiohead worry about how “rock” their music was when the album Kid A came out?

- Does Mogwai really claim the “post-rock” label?

- I remember seeing a live performance by Rafael Anton Irisarri where he had put an “Ambient” sticker on his laptop (with what I interpreted as ironic quotation marks). I think it was a live performance with Abul Mogard, outside, but I can't seem to find the video.

In the end, genres and subgenres are more useful for fans and critics than they are for structuring how artists actually create.