>The concept did not originate in videogames.

Yes it did. "noclipping out of reality" is a metaphor that is nonsense outside the context of videogame worlds. The 4chan copypasta that popularized the Backrooms meme doesn't mention video games but that particular post is not the origin of the backrooms concept.

There are literal backrooms you can noclip into existing in games that that predate that 4chan post by several years