Around me, I see many such daily wage laborers, rickshaw pullers or agricultural laborers, who remain at the same position from which they started their life even at the end of their age. It's not like they don't work hard.
It's true they're working hard, but sorry to say this... those jobs you mentioned above mostly don't have any prospect. I mean, what you can expect from someone who work without skill and even they already have working for 5 years, it doesn't make them already have a skill since what they do are jobs without skill in the first place.
Obviously it's hard since you said they work for 12 hours, the choice is they need to looking for a new job from other company that didn't require to work for 12 hours, so they can use few hours to develop themselves.
Hardworking is a necessity for surviving but sometime it doesn't matter how hardworking one can be but the ability for an individual to work smart, discover his/her talent where necessary and know how to apply it in order to make the best utilization of any little available opportunity. There many people that work for 20hours daily without a tangible wages but smart person that now how to discover opportunities can work for less than 20hours daily and make a better income.
Based on your opinion, I can give an idea that this is realistic regarding some employment conditions in society, especially for those in the lower economic strata. It is true that hard work is a necessity to survive, but hard work alone does not necessarily mean you can get a decent life.
Having skills and knowledge can increase the key to improving one's career and improving one's economic life. Education is an important investment for someone to improve their qualifications and competitiveness in the job market.
Apart from that, the ability to work smart, be able to identify talents, and take advantage of opportunities are factors in achieving success. A person needs to actively look for opportunities within himself to provide room for growth and development in looking for work.