Everyone is individual, just because you might do a manual job, doesn't automatically mean you'll die younger than someone who does another job. It also comes down to lifestyle, family medical history, etc.
Personally I don't consider myself particularly well educated, I've had a manual job for 30 odd years and plan to retire at 55.
I took an interest in my pension/retirement at an early age, realised what I'd get from RM probably wouldn't be enough(we still had a final salary scheme then) and I did something about it, and will be able to provide an income of not drastically less than my current full time RM wage.
I've planned for years, based on my own circumstances and should be ok, but I'm not sure about many others I know.
I've read comments on here like 'I won't need any money in my 70's and 80's', but I have parents in their late 80's and have seen at first hand that they still need money, they just spend it on different things.
They're still living at home any coping but obviously not as active as they once were, and ultimately the longer they live, the more likely they are to need professional care – and the costs are frightening!
The population is ageing and many have a lot of money tied up in property. Unfortunately in a lot of cases that property will be sold to pay for their care, leaving their offspring who expect to get a nice inheritance, with nothing.