I only skimmed it, but I'm feeling this is exploring the world of fashion models more than Instagram per se, or at least being in that world incents a certain behavior.
It's fine to wonder if tech if serving us correctly, but also it's good to know that some people have very different lives from us, and thats ok too.
Thing is, its not just happening in the 'fashion model' world. The focus seems to be coming down to 'regular' people. Artists, street musicians, developers, moms and dads, single parents, cat lovers, bike enthusiasts, amateur chefs... you name it.
If you have a sizeable following, you have the option to sell your soul to one or many companies who will then organise your social media flow for you, suggesting what to post, when to post, and what to hashtag. All for a fee or discounts on their products.
At least when you see a racing driver's suit plastered with sponsor logos, you know they've paid him/her or the team for the privilege of doing so. Nowadays it is not so obvious, but rather the inference is that it is all natural and common and 'real'.