I walk by a twitter building every day. Probably about 500 people, maybe more. What are they doing in there? They sell ads, manage ad accounts, moderation, data protection audits... stuff that David Graeber wold call BS jobs. Now... I'm not in the same camp as him entirely. I think it's rash to just write off 70% of modern, white collar work as "paperwork" that could just go away.... but I'm not entirely not in his camp too.
Either way, that building is full of "marketing and social media" graduates doing stuff that doesn't need to be done for twitter to be twitter. Twitter was twitter before they had all those people.
You could call what twitter does creative work. That resonates with me. They invented a communication method with all sorts of cultural impact and value. That's creative. But, extending that to the median employee... I think we might divert here.
I think you have your finger on an interesting point, even if I don't know how to articulate it. A generation ago, a lot of the ecoomy could be measured in stuff with value that one could reason about. Cars, tothbrushes, haircuts, podiatrists.... You can count and weigh and value that stuff. Media was always more abscure. The tv viewer mightn't be the customer. The purpose of a paper might be do get a classifieds insert into your hands.
Once you throw in social/user-generate services make the picture more messy. Once you go to Google/FB territory, it's all very obscure. Half of what they do doesn't have any direct economic benefit to them, it's more a way of keeping them in a massively powerful position.
I'm not sure creative is the right word, but here's somethign going on. Ever increasing (already majority) sections of the economy are producing very ethereal things, with obscure business models...