Plenty of kids would probably be willing to work in manufacturing, if the jobs didn’t pay complete and utter sh!t.
Plenty of manufacturing jobs don’t pay much more than a job making and selling fast food.
I’m nit sure what the major hazards of working in a fast good restaurant are, but getting burn by frying oil, or s jot grill, are probably the major hazards, other than getting attacked by an irate customer.
Meanwhile, manufacturing jobs can routinely involve cutting injuries where you can loose gingers, or maybe an arm, or get crushed, or yanked into large machinery, or get weird cancers from various chemicals, or dusts, etc., etc.
You also probably have to buy your own clothes for the manufacturing jobs (which can wear out quickly) whereas the uniforms at fast good jobs are supplied by the employer (or are at least supposed to be).
Plenty of manufacturers don’t hive a **** about safety, and will routinely short even cheap basic things like box cutter blades. (Yes, sharp blades are legally required, or a way to sharpen the blades).
Even then, I suspect a certain portion of younger people would take those jobs, rather than a fast food job, but most are smart enough not to.