But after lifetime of manual work most workers still have problems with spine and joints.
Manual workers not only face health problems but also risk and loss if they cannot save some money before they grow old and lose their ability to work. They will even work until they die. Meanwhile, those with degrees and working at state-owned enterprises will enjoy many benefits during their working time as well as receive pensions when they retire. Not only that, if they have good relationships, their children will have more job opportunities and more chances for career advancement in the future.
The benefits of having a degree are huge, we should not just because some students graduate and become unemployed think that degrees are useless, and spread the mindset that no degree is needed to the younger generation. It not only ruins their future but it can ruin the future of the entire nation.
It all depends on the type of contract they are signed, or maybe if they even work without signed contract. If they work without contract they future is not very good, as they won't receive pension benefits or have health insurance. And specially if work inspection catches them to work illegaly. I doubt that employer that employs workers without contract care for their workers health and safety, so they probably try to overwork workers to get the most work for daily wages. So yes you have good arguments too.