I have a theory about why the music can nonetheless be heard this way. Below are twelve possible metrical interpretations of the opening of the song. (You will want to click on the image to see detail.) The ordering from left to right corresponds to the relation between the first sound of the song and the first notated downbeat: in the middle, they match; to the left, the first sound is an eighth note earlier than the first downbeat; to the right, the first sound is an eighth note later than the first downbeat. The ordering from top to bottom corresponds to the length of duration that can be grouped into threes: eighth note for the highest, quarter note for the second highest, half note for the second lowest, and whole note for the lowest.
Music that is not faded represents a line in the texture that works with its notated meter. The fact that there is no single interpretation that is completely not faded signifies that the meter is not straightforward. However, note that, although the brown-bordered metric interpretation is entirely faded, this interpretation is the only one adjacent (like a chess king is adjacent) to five of the six interpretations (thinly bordered) that have a line that is not faded. This brown-bordered metric interpretation is their center and their best approximation (in two dimensions!), even though the music has no content that would directly support this metric interpretation. This is like the fact that there is usually no town located at the mean population center of a country.
This metaphor seems appropriate given the song’s extra-musical content and context. The Kashmir region in South Asia is not a separate state, but rather defined politically only through its division between India and Pakistan. However, according to Wikipedia, Led Zeppelin’s singer Robert Plant was initially inspired not by this part of the world but by a place similarly liminal: the barren “waste lands” of Southern Morocco between the cities of Guelmim and Tan-Tan.