I went to a Russel Group uni, and one of the things I will never forget is some "entrepreneur" kid telling me that he never worried about taking financial risks because he always trusted that there would be more money.
In the same vain, not everyone could set up a YouTube account like Grace did. For me, coming from a low income household, social media was - and still is - a pretty risky business. Without family connections, my best chance at success was my education and having a professional public persona, so when I was at uni I studied nonstop and spent my free time doing extracurricular that would look good on my CV. Doing something like YouTube was just not an option: I never had money for expensive gym memberships or even proper gym clothes (let alone to do a clothing haul); I was always conscious that appearing online in sexy poses or in an immature way could jeopardise future career opportunities (my blog, Twitter and LinkedIn were for networking, rather than hobbies); and I couldn't afford to take up hobbies that would take time away from my studies. So I never took the risks that someone like Grace would take because the potential negative outcomes were just too high. This isn't just my personal experience either - the research into the relationship between childhood socioeconomic background and adulthood socioeconomic positioning says the same.
The reality is that Grace would have had to actively try to fail and derail her life for her to move down the socioeconomic ladder. Prior to going to uni, Grace didn't just work in a crappy low skilled job like most of us did, she had a coveted paid internship. Most kids wouldn't even know how to find such an opportunity, let alone get one. Even if Grace's business failed tomorrow, she'd still get a top notch job somewhere despite having a very unprofessional, immature social media presence. Consequently, Grace has been able to take social and economic risks most people aren't able to take, let alone have a positive outcome from.
Apologies for the long rant - it's just a topic I feel very passionately about!