A PhD makes it more difficult to find a job because bigcorps (1) want to indoctrinate and mold you based on company doctrine and culture, and (2) pay based on age.
(1) Japanese bigcorps have extensive on the job training programs which bring relatively specialized new grads up to speed. In fact I think it does a great job at getting nearly all new hires up to median performance within the company. Think of it as relying on mass producing "good employees", rather than focusing on finding "great employees".
(2) Japanese bigcorps are organized such that promotions and pay increases happen based on seniority. This is especially the case at the lower ranks, where everything is very methodical and planned out. Promotion cycles tend to happen every 3 years, with boolean results. Raises happen methodically every year according to HR's tables (though these get phased out when you get more senior -- part of the cost cutting efforts in the last 20 years).
Combine these two factors and companies want young, cheap "good enough" talent to join their company, after which they will train them according to their corporate flavor. Hiring a PhD means that you have to pay them higher than the undergrad, even though you're going to put them both through the same training cycles. Unless there's a really good fit between the doctorate candidate's research and what a team wants (or lab-corporate connections), companies will shy away from hiring PhDs.
What about for jobs where research skills are specifically necessary, like in corporate science and technology labs? Do the bigcorps find more value in hiring an undergrad and providing them training on how to do research?
For such jobs, big corps do hire PhDs. These jobs are almost always in a research department (i.e. they won't hire a PhD to code). But these jobs are maybe 1% of all jobs in big corps.
Nowhere near 1% in my experience. Also, even in research arms, many masters level students are accepted (though it really depends on how low level the research activity is at that particular company, so this is going to vary wildly among different companies)
(1) Japanese bigcorps have extensive on the job training programs which bring relatively specialized new grads up to speed. In fact I think it does a great job at getting nearly all new hires up to median performance within the company. Think of it as relying on mass producing "good employees", rather than focusing on finding "great employees".
(2) Japanese bigcorps are organized such that promotions and pay increases happen based on seniority. This is especially the case at the lower ranks, where everything is very methodical and planned out. Promotion cycles tend to happen every 3 years, with boolean results. Raises happen methodically every year according to HR's tables (though these get phased out when you get more senior -- part of the cost cutting efforts in the last 20 years).
Combine these two factors and companies want young, cheap "good enough" talent to join their company, after which they will train them according to their corporate flavor. Hiring a PhD means that you have to pay them higher than the undergrad, even though you're going to put them both through the same training cycles. Unless there's a really good fit between the doctorate candidate's research and what a team wants (or lab-corporate connections), companies will shy away from hiring PhDs.