It's an amusing term for sure and definitely an outcropping of the internals at FAANG (or maybe MS as well) culture. Like, it almost sounds denigrating. "I was just an individual contributor"; like, the people who do the real work, y'know, they're out there doing the difficult work of herding cats to tell them which protobufs to move from A to B, while the ICs are, y'know just ICing doing the actual protobuf shuffling :-)

It's just about promo culture @ Google, etc. and not in fact I think a reasonable principle of how good software gets built.