It's not noun. I think it is verb.
~ゆく means "~ing"
崩れゆく is same for 崩れていく
but 崩れゆく lets me feel more lyrical than 崩れていく.
崩れて「いく」＝行く(be going to)
ゆく is formal and literary (and old) expression of いく.
Perhaps lyric writer thought that 5-sound word is better than 6-sound one in this part for rythme or groove when he was writing.
I think "omission" is defferent a little bit.
I can't tell you a detail of this with my poor English skills and vocabulary.
This called "体言止め"(taigen dome)
体言(taigen) = 名詞(meishi) = noun
止め(tome or dome) = stop or end
This is japanese "figure of speech" technique.
To put a noun at sentence's last for giving an aftertaste to it.
抑制＝noun at sentence's last.
〇死にゆく惑星(shiniyuku wakusei : dying planet)
惑星＝noun at sentence's last.
difference of 崩れゆく抑制 between 抑制が崩れゆく(why 崩れゆく抑制 is used this time?)
This is just simply "sentence". no good feeling no aftertaste.
Put noun at last. We Japanese get the impression as if this sentence doesn't be end and is still continued.
But actually, sentence is end. So we japanese feel a bit aftertaste from this part.