I can't criticise Holly's get up and go - I applaud her for having the overview, organisational skills and perseverance to get a successful tutoring business off the ground at her age, and she clearly prepares for her sessions/takes them seriously. I wonder if her students (or their parents if they're paying) feel as though they've got value for money. I wonder if they are families that have used or would have used tutors anyway, or whether she's helping people who might not have otherwise reached out.
I've watched a fair number of her videos and have never heard her mention accessibility, so I would assume that this wasn't a key motivator for her. I also think that if she was passionate about spreading her love of the subject then she would have likely thought of ways of incorporating some version of it into her 'normal' videos, especially after her finals when she has had more time to spare.
I think maybe she sees her knowledge as hard-won and precious, and she doesn't want to undersell it or give it away freely, which I suppose is her prerogative.
One idea to open up her service might be to have a cheaper 'package' available where people pay less for access to a number of her recorded sessions rather than a one-on-one experience. I don't know if that would work.
I'm more worried about her giving advice regarding personal statements, as we've seen - and she admits - that she isn't that well rounded and has misunderstood/devalued the value of non-academic life and is unused to motivators besides achieving good grades. I don't think she would be able to draw out of people things that compliment and strengthen their application. She's not a careers/guidance counsellor or someone who has seen many personal statements/applications and evaluated what makes these successful. I worry that she'd actually end up weakening someone's application by giving them skewed advice.
It feels a bit mean but she has not been accepted onto every course of her choice (like medicine or the full gamut of universities she has applied to recently), so we know that she doesn't have all the answers. That's normal, and it's a lot of pressure to succeed at everything you try - I wouldn't expect anyone of that age to have all the answers - but I also wouldn't expect to pay for their advice/experience.
I worry that someone who comes from a different background from her would find their motivations/achievements devalued, and that could have an impact on their direction and self-esteem. University applicants are at a delicate age and facing lots of pressure, and I'd hate that young women wanting to go into a STEM subject could be discouraged - either directly or indirectly. They may be able to gain different things from a university course than Holly did, and this would not be a less successful experience, although Holly may not see this.
I wouldn't even necessarily trust Holly's assessment of an application for her course at Cambridge (I don't know what percentage of people she helps are applying for this), let alone a different course at a different university, although maybe I'm doing her a disservice.