I think you are right; small high street studios seem, to me, the most vulnerable because everybody has a camera and not all small businesses can produce better work than can some of their customers - and then it's just a matter of time.
I would imagine that high-end advertising, fashion and also product photography simply has to exist in order to allow manufacturers to showcase their products. But magazines - I wonder. So much is now online, and magazines have become very expensive for what is, mostly, terrible design with too much content crammed onto every page. I can really see the big glossies fade away. Compare the leading fashion magazines of twenty-five years ago or more, with clean covers and minimal interference on the pictures, with the state of some of them now: just like catalogues. It's all going southwards insofar as style is concerned. IMO.