The experience of my neighbors from an industrial city is 100 per cent opposite. Physical jobs tend to consist of endless repetitive tasks that put a huge strain on certain joints and sinews while leaving other parts of your body idle. And many physical jobs will expose you to health risks such as breathing dust.
All the miners, steel workers, construction workers etc. I knew had major problems with their joints around 35 years of age and none of them could continue to work in their original job after 50.
On the other hand, negative effects of sedentary work can be mostly compensated by not eating processed crap (to prevent obesity) and exercising moderately three or four times a week. Plenty of people do that.
I think you’re envisioning jobs with high skill requirements or low demand, or a mix of both. Like landscaper for the town, or garbage truck operator.
Otherwise you’ll generally be met with a combination of RSI, hazardous product ingestion (dust, paint fumes, exhaust…), allergies, injuries, or sheer overwork.
Working a low wage low level physical job is more often than not closer to Amazon warehouse worker than artisans healthily exercising their bodies.
Most office jobs don't involve that much typing. You can also buy keyboards with softer switches. (RSI was more common in the days of mechanical typewriters.) Low physical acitivity can be made up for going to the gym after work.
It sounds to me you never did a day of manual labor in your life.
My point, was that both physical/labor intensive jobs and office jobs bring their own types of workplace related problems. And just because the job may carry with it a risk of physical injury doesn't mean the job should be automated. Afterall, any type of movement the body does carries with it a risk of injury.
While your point is true that every profession has an injury risk, it's the type of comment that misses the point: there is a significant difference in those stats, and by trying to equate them, you are purposely watering down the significance of one where injuries are more prevalent (or at least harder).
It's a response similar in style to deflecting from attempts to solve one crisis by introducing another crisis.
This is a pipe dream of white collar who never did any actual, real, physical job for a very prolonged time. It's not like going to the gym for free or doing just the right amount of sport. It's something that stresses your joints and your muscles day in day out. Obviously you will partly get used to it and be "more fit" than a white collar but you will also develop back pain and joints pain.
Not for my carpet-fitting granddad. And it's not like he has a private pension. Desk job damage can mostly be undone by proper exercise: it takes surgery to fix knees.
Standing all day is also worse for your back than sitting all day. Even being a shop assistant is harder on your body, and particularly your back, than sitting at a desk. (Alternating, i.e. an office job with a sit/stand desk, is best.)
The primary issue is complete lack of inactivity (a large component just being weight gain), which you can combat by exercising outside of the office.
Also just want to add that working in a physical job for 50 years is much better for your body than sitting at a desk for 50 years.