It was the 'advertising campaign' of the Industrial Revolution, and like Gerald highlighted, it worked for a very short time, for a very small group, already in an advantaged position. The reason it's a useful tool, even in modern Neolliberal Economics, is because it shifts focus, it pits working-class, against working-class, with the dream they can be middle-class, and middle-class, against middle-class with a dream to be upper-class. That rivalry, within Classes, allowed the impoverishment while pretending there was a development, the 1-income household was replaced by the 2-income household, and a sneaky development was that wage-development stalled(you need 3 average wages today, to reach the standard of life 1-income covered in the 1970s).
The latest 'trick' was the 2008 crisis, since 2008 the Middle-Class lost 40% of it's economic-development, the Working-/Lower-Class lost 10%, and the Elite, the Upper-Class has never made more money, quicker(latest numbers suggest a growth of wealth of the Elite of 15%+) So it was a trick to make us work harder, for less reward, and blame each other, instead of the people exploiting this system.
It's not necessarily a myth, but it's beyond unrealistic to apply it to everyone, when it only applies to a few. No matter how hard one works, not "everyone" can "get on". Most new businesses fail, not everyone has the academic potential or more importantly connections to get on in top professions, and so on.
It's not what you know, it's who you know. The myth sounds like some old "American Dream" nonsense, same philosophy.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.