Anecdata: I'm currently in the middle of interviewing with a wide slate of mid-size SV companies, and not one has asked for code samples. It's all a mix of whiteboarding, on-site coding, phone-screen coding, or take-home coding.

So at least for 15-year veterans it does not really seem to be much of a thing. Although I do secretly wish they would discover my 4-digit GitHub user id, that's gotta be worth some kinda programmer-cred right?