The idea that press attention and public interest correlates or should correlate to "position in some old British formal order" is pretty weird if you think about it.
Most people don't care about shit like that, it's just a small number of older British royal fans who put weight into these things. Yeah of course order of succession is important to the royals, but outside of the monarch the general public mainly don't know or cares anything about this arcane rank and style stuff.
It's like all the posters saying Harry should be stripped off his title and that way the press and public would lose interest. In reality if Harry was stripped of his title no one would notice or care at all and everyone would still call him Prince Harry, the way the world always called his mum Princess Di when she never even held or could legally hold that title.
Because that's just not how the world works. Look at any celeb industry, tons of aspiring actors with impeccable training and on-paper qualifications never get the tiniest bit of attention, whereas people who have never attended an acting class in their life become superstars. Reality contestants who don't do anything become household names, just because they're attractive and charismatic. It really doesn't matter at all what "qualifications" someone has on paper to be famous, the only real qualification to be famous is the general public finding something about you fascinating.
In the real world, the level of media attention a person receives depends mostly on their personal charisma, their level of physical attractiveness, and their ability to generate gossip. H&M are very charismatic and clearly the general public are fascinated by them (if they weren't, the media wouldn't print a billion stories about them). Kate is beautiful and wears lovely clothes but she's not very interesting or charismatic, and both Charles and William are dull as ditchwater and just don't capture the public imagination or create fascination. That's why they trot the kids out all the time, because they're not interesting enough to the wider general public to generate that much positive attention by themselves.