I think the lack of scial mobility is showing that hard work doesn't pay as such.
Unless of course you consider that most, if not all, people who are at the lower end of the scale wage wise also are the ones who never work hard....
Unfortuntatly, the meritocracy we are supposed to have in this country isn't what they tell us it is.
People who start with nothing rarely arrive at the top as millionaires.
Not wo a good education (given by their parents, not just 'private' education but also the opportunity to talk about different subjects, what happens at school, go to museums etc etc), some networking opportunities (eg the possibility to do some placemnets at the 'right place' or to do an internership even if you aren't paid etc etc).
Having the 'right' training, the opportunity to retrain later on etc... is a privilege as such and will make a huge difference.
And then even hard work will not be enough to be promoted.
Eg when I was working in a factory, some of the people of the shop floor (MNW type of stuff) were hard working, conscientious etc... They knew exactly what they had to do, the product they were working on etc.. Next step on the ladder for them? Being a team leader and organisig peole around their work.
Would all of them been able to do that? NO because the skills needed to do that were vastly different and they didn't have the knowledge or the ability to do so. Lacking basic skill such as fluent reading/writting and numeracy is already an obstable. Then they were missing skills that are actually learnt at home on organisation, self organisation or what is losely called 'people skills'.
Another example for me are some soletrader such as a plumber. The type who does his job very well but is completely scattered, has to go back home 3 times because he is misisng tools, hasn't planned ahead etc... It's not the 'working hard' (ie putting the hours, doing the job well, getting recommendations) that is missing, it's the 'working well', skills that somehow are assumed to be known by people and aren't always.