@MangshorJhol
I am not sure what the point of most of your post is.
Firstly, Gwyneth almost being a decade older than MM , has nothing to do with anything. It's a bit like me comparing other older women like Heather Locklear, Meg Ryan etc. All were big in their prime.
The main thing is that Gwyneth was at her prime fame around 2001, and Meghan's prime fame is NOW. This is the important fact. This means people between 25 and 45 are most likely within the same vibes of her makeup/lifestyle etc. They are also prominent users of SM and these kind of blogs. The younger for fashion probably (think Grazia), the older for family lifestyle (with kids most likely at home still).
Perhaps the problem is for you is that you, specifically, are simply not her market.
She does not have to have cameras following her all around. She could do slots showing her making food (she did this on Tig /tutorials on make up and decorations etc.). Martha Steward/ Jo Malone / Lulu Guinness/ Jo Malone and everyone actually, did not have to show us anything about their personal lives to have successful brands. It's all about marketing.
For the list you gave, I only knew less than a handful had brands, tbh. So all boils down to who your market is, I guess. Evidently, MM does have a market.
I don't know if Angelina Jolie was doing charity and ambassador work when she was up and coming (well, as a nepo baby, she probably was never 'up and coming'), but I only heard about her work later in her career. As for the Obamas/Clintons, they were Lawyers/Potus/Producers, they didn't start off their careers as producers or in the field like Spielberg . MM was Actress/Royal/Producer.
I'm not the one who suggested a charity link for the Tig, but I think that is a splendid idea. To be linked with Archewell, just as Production/Audio are. Some Capsule/Food/Bakery etc. could easily be linked to the Foundation section.